The vapour also contains free radicals, highly oxidising substances which can damage tissue or DNA, and which are thought to come mostly from flavourings.
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Intense heat means that, once bottled, the wine has to be transported in lorries filled with dry ice to stop it oxidising on the way.
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In particular, the promoted genes relate to cell-wall synthesis, DNA repair and the production of compounds that mop up harmful oxidising agents produced by sunlight.
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"The eruption injected a huge amount of sulphur dioxide into the stratosphere, which would have quickly spread across the world, oxidising to form sulphate aerosols," Schurer said.
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It contains about 70 carcinogens, as well as carbon monoxide (a poison), particulates, toxic heavy metals such as cadmium and arsenic, oxidising chemicals and assorted other organic compounds.
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To stop the powder oxidising and being contaminated by impurities in the air—or worse, exploding—that process needs to be carried out in a chamber filled with an inert gas.
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PdF4 is a strong oxidising agent and undergoes rapid hydrolysis in moist air.
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The upper Oxidising Flame at consists of the non-luminous tip of the flame.
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Uranous salts are converted into uranic by boiling with nitric acid or other oxidising agents.
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The Oxidising Angel is the first EP from German futurepop band Blutengel. It was released as a single CD. It featured a cover of Cry Little Sister the theme from the film The Lost Boys originally by Gerard McMann. On the original CD release, tracks 12 & 13 were hidden as part of track 11, The Oxidising Angel (Single Edit) which put the track time at 11:56. A music video was released for the title track, The Oxidising Angel.
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Syntrophobacter pfennigii is a species of syntrophic propionate-oxidising anaerobic bacterium. Strain KoProp1 is the type strain.
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Potassium permanganate functions as an oxidising agent. Through this mechanism it results in disinfection, astringent effects, and decreased smell.
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It can be made by oxidising nickel nitrate in a cold alkaline solution with bromine. A mixed oxidation state hydroxide Ni3O2(OH)4 is made if oxidation happens in a hot alkaline solution. A Ni4+ hydroxide: nickel peroxide hydrate NiO2, can be made by oxidising with alkaline peroxide. It is black, and unstable and oxidises water.
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It is also used in molecular biology as an oxidising agent, for example to oxidise free thiols to form disulfide bonds in proteins.
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The gum is stable, probably combustible and incompatible with strong oxidising agents. Its toxicity is low, but inhalation of dust may cause allergies.
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Sulfobacillus acidophilus is a species of moderately thermophilic mineral- sulphide-oxidizing bacteria. It is Gram-positive, acidophilic and ferrous- iron-oxidising as well.
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The periodatonickelates are a series of anions and salts of nickel complexed to the periodate anion. The diperiodatonickelates with nickel in the +4 oxidation state are powerful oxidising agents that are capable of oxidising bromate to perbromate. Sodium nickel periodate, NaNiIO6·0.5H2O and potassium nickel periodate, KNiIO6·0.5H2O were discovered in 1949 by P. Ray and B. Sarma. These double salts are coloured dark purple.
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There was a total of 1.9 tonnes of AZDN in oxystore 2. The powder released reacted with sodium persulphate, an oxidising agent, which was stored adjacent to it. It was also capable of burning in air. An immediate underlying cause was that AZDN, a reducing agent, which was a chemical in regular use by AC had, for store- keeping purposes, been wrongly classified, in 1989, as an oxidising agent.
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The anode is the oxidising electrode and as a result has a lower localised pH during electrolysis which also promotes desorption of some organic pollutants. Regeneration efficiencies of activated carbon in the anodic compartment are lower than that achievable in the cathodic compartment by between 5-20% for the same regeneration times and currents, however there is no observed residual organic due to the strong oxidising nature of the anode.
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"Candidatus Scalindua brodae" is a bacterial member of the order Planctomycetes and therefore lacks peptidoglycan in its cell wall, has a compartmentalized cytoplasm. It is an ammonium oxidising bacteria.
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Their unique abilities to withstand high temperatures close to hydrothermal fluids enables them to prey upon sulphur-oxidising bacterial mats which grow close to the metal rich vent plume.
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HOCl is classified as Non-Hazardous by the Environmental Protection Agency in the US. As any oxidising agent it can be corrosive or irritant depending on its concentration and pH.
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They are ammonium oxidising bacteria found in marine environments. The genus Ca. Scalindua are the most abundant anammox bacteria in marine environments, so they are vital to the Earth's nitrogen cycle.
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A reducing flame (fuel rich) gives trouble with soot deposits in the weld. An oxidising flame burns the lead and creates lead oxide dross, leading to poor welds with low malleability.
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Most applications of noble gas compounds are either as oxidising agents or as a means to store noble gases in a dense form. Xenic acid is a valuable oxidising agent because it has no potential for introducing impurities—xenon is simply liberated as a gas—and so is rivalled only by ozone in this regard. The perxenates are even more powerful oxidizing agents. Xenon-based oxidants have also been used for synthesizing carbocations stable at room temperature, in solution.
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Although dichlorine is a strong oxidising agent with a high first ionisation energy, it may be oxidised under extreme conditions to form the cation. This is very unstable and has only been characterised by its electronic band spectrum when produced in a low-pressure discharge tube. The yellow cation is more stable and may be produced as follows:Greenwood and Earnshaw, pp. 842–44 :Cl2 \+ ClF + AsF5 This reaction is conducted in the oxidising solvent arsenic pentafluoride.
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Mariprofundus ferrooxydans is a neutrophilic, chemolithotrophic, Gram-negative bacterium which can grow by oxidising ferrous to ferric iron. It is one of the few members of the class Zetaproteobacteria in the phylum Proteobacteria.
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Like all halogens, it is thus one electron short of a full octet, and is hence a strong oxidising agent, reacting with many elements in order to complete its outer shell.Greenwood and Earnshaw, pp. 800–4 Corresponding to periodic trends, it is intermediate in electronegativity between fluorine and bromine (F: 3.98, Cl: 3.16, Br: 2.96, I: 2.66), and is less reactive than fluorine and more reactive than bromine. It is also a weaker oxidising agent than fluorine, but a stronger one than bromine.
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SHARON (Single reactor system for High activity Ammonium Removal Over Nitrite) is a sewage treatment process. A partial nitrification process of sewage treatment used for the removal of ammonia and organic nitrogen components from wastewater flow streams. The process results in stable nitrite formation, rather than complete oxidation to nitrate. Nitrate formation by nitrite oxidising bacteria (NOB) (such as Nitrobacter) is prevented by adjusting temperature, pH, and retention time to select for nitrifying ammonia oxidising bacteria (AOB) (such as Nitrosomonas).
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Population of Kiwa around a hydrothermal vent Unlike Kiwa hirsuta and Kiwa puravida, which are notable for having a dense covering of setae on their elongated chelae, this species has shorter chelae, with most of the setae concentrated instead on the ventral surface of the crab. Filamentous bacteria were found on the setae and similar-looking sulfur-oxidising bacteria have been found amongst the setae of Kiwa hirsuta and Kiwa puravida. It has been hypothesised that these sulfur-oxidising bacteria, which fix carbon from the water by oxidising sulfides in the hydrothermal fluid, are a significant source of nutrition to the crabs. The Hoff crabs were found living adjacent to and on the sides of hydrothermal vent chimneys living in close proximity to fluid emanating from the chimneys at temperatures greater than of .
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Oxidation of mesitylene with nitric acid affords trimesic acid, C6H3(COOH)3. Using manganese dioxide, a milder oxidising agent, 3,5-dimethylbenzaldehyde is formed. Mesitylene is oxidised by trifluoroperacetic acid to produce mesitol (2,4,6-trimethylphenol).
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Methylocella tundrae is a species of bacterium. It is notable for oxidising methane. Its cells are aerobic, Gram-negative, non-motile, dinitrogen-fixing rods. Strain T4T (=DSM 15673T =NCIMB 13949T) is the type strain.
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400, no. 6743, pp. 446–449, 1999 and the first identified anammox organism was named Candidatus "Brocadia anammoxidans."J. G. Kuenen and M. S. M. Jetten, 2001 "Extraordinary anaerobic ammonium oxidising bacteria," ASM News, vol.
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AgN3, like most heavy metal azides, is a dangerous primary explosive. Decomposition can be triggered by exposure to ultraviolet light or by impact. Ceric ammonium nitrate is used as an oxidising agent to destroy in spills.
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Leptospirillum ferriphilum is an iron-oxidising bacterium. It is one of the species responsible for the generation of acid mine drainage. It is of particular relevance in South African commercial biooxidation tanks operating at 40 °C.
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Desulfovibrio marrakechensis is a bacterium. It is sulfate-reducing and tyrosol-oxidising. Its cells are mesophilic, non-spore-forming, non-motile, Gram-negative, catalase-positive and straight-rod-shaped. They contain cytochrome c(3) and desulfoviridin.
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Pyridine-N-oxide is the heterocyclic compound with the formula C5H5NO. This colourless, hygroscopic solid is the product of the oxidation of pyridine. It was originally prepared using peroxyacids as the oxidising agent. The molecule is planar.
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In work undertaken in collaboration with Arthur F. Ferris, Emmons reported that in situ generated trifluoroperacetic acid was capable of oxidising aniline to nitrobenzene, an observation which pioneered the applications of this peroxy acid as an oxidising agent in organic chemistry. Emmons went on to discuss the preparation of trifluoroperacetic acid and numerous applications of the new reagent, including: oxidation of nitrosamines to nitramines; the Baeyer–Villiger oxidations of ketones to esters; and the conversion of alkenes to epoxides (in the presence of a buffer) or to glycols (without the buffer).
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As the melting point of lead is so low a high-temperature furnace is not required and it can be fuelled with wood. It is important that this takes place in a reducing atmosphere, i.e. one with little oxygen, to avoid the lead oxidising; the cakes are therefore well covered by charcoal and little air is allowed into the furnace. It is impossible to stop some of the lead oxidising, however, and this drops down and forms spiky projections known as ‘liquation thorns’ in the channel underneath the hearth.
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For example, ceric ammonium nitrate is a common oxidising agent in organic chemistry, releasing organic ligands from metal carbonyls. In the Belousov–Zhabotinsky reaction, cerium oscillates between the +4 and +3 oxidation states to catalyse the reaction. Cerium(IV) salts, especially cerium(IV) sulfate, are often used as standard reagents for volumetric analysis in cerimetric titrations. The nitrate complex is the most common cerium complex encountered when using cerium(IV) is an oxidising agent: it and its cerium(III) analogue have 12-coordinate icosahedral molecular geometry, while has 10-coordinate bicapped dodecadeltahedral molecular geometry.
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Cupellation involved removing the lead from a silver-rich alloy by oxidising the lead to litharge, leaving the silver behind. Pattinson's process was economic with as little as 2 to 3 ounces (about 75 grams) of silver per ton.
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PtF6 is a strong fluorinating agent and one of the strongest oxidants, capable of oxidising xenon and O2. PtF6 is octahedral in both the solid state and in the gaseous state. The Pt-F bond lengths are 185 picometers.
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It protects itself from progressive corrosion by oxidising on exposure to air and moisture. The protective film gradually darkens with time and assumes a pleasing texture and colour; if exposed near the sea the colour tends to be grey.
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The type order is the Hydrogenophilales. The Acidithiobacillia contain only sulfur, iron, and uranium-oxidising autotrophs. The type order is the Acidithiobacillales, which includes economically important organisms used in the mining industry such as Acidithiobacillus spp. The Oligoflexia are filamentous aerobes.
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The atmosphere within a kiln during firing can affect the appearance of the finished wares. An oxidising atmosphere, produced by allowing an excess of air in the kiln, can cause the oxidation of clays and glazes. A reducing atmosphere, produced by limiting the flow of air into the kiln, or burning coal rather than wood, can strip oxygen from the surface of clays and glazes. This can affect the appearance of the wares being fired and, for example, some glazes containing iron-rich minerals fire brown in an oxidising atmosphere, but green in a reducing atmosphere.
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Krypton difluoride is primarily a powerful oxidising and fluorinating agent: for example, it can oxidise gold to its highest-known oxidation state, +5. It is more powerful even than elemental fluorine due to the even lower bond energy of Kr–F compared to F–F, with a redox potential of +3.5 V for the KrF2/Kr couple, making it the most powerful known oxidising agent, though could be even stronger: : 7 (g) + 2 Au (s) → 2 KrFAuF (s) + 5 Kr (g) KrFAuF decomposes at 60 °C into gold(V) fluoride and krypton and fluorine gases: : KrFAuF → (s) + Kr (g) + (g) can also directly oxidise xenon to xenon hexafluoride: : 3 + Xe -> \+ 3 Kr is used to synthesize the highly reactive BrF cation. reacts with to form the salt KrFSbF; the KrF cation is capable of oxidising both and to BrF and ClF, respectively. is able to oxidise silver to its +3 oxidation state, reacting with elemental silver or with to produce .
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Agents such as hydrogen peroxide, elemental chlorine, hypochlorous acid (chlorine water), bromine, bromine water, iodine, nitric and oxidising acids, and ozone react with sensitive moieties such as sulfide/thiol, activated aromatic rings (phenylalanine) in effect damage the protein and render it useless.
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Periodates are powerful oxidising agents. They can oxidise catechol to 1,2-benzoquinone and hydroquinone to 1,4-benzoquinone. Sulfides can be effectively oxidised to sulfoxides. Periodates are sufficiently powerful to generate other strong inorganic oxidisers such as permanganate, osmium tetroxide and ruthenium tetroxide.
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Holmium(III) bromide is formed as a result of the reaction: :2 Ho(s) + 3 Br2(g) → 2 HoBr3(s) Holmium(III) bromide reacts with strong oxidising agents. When involved in a fire, holmium bromide may release hydrogen bromide, and metal oxide fumes.
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Microcosmic salt is used in the laboratory as an essential ingredient of the microcosmic salt bead test for identification of metallic radicals on the basis of the color they produce in oxidising or reducing flame, in hot or cold condition. Microcosmic salts form a tetrahydrate.
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Yet other bacteria can convert methane, back into living matter, by oxidising with other substrates. Bacteria can reside at great depths in sediments. However sedimentary organic matter accumulates the indigestible components. Deep bacteria may be lithotrophes, using hydrogen, and carbon dioxide as a carbon source.
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She was amazed with the show and got to meet Chris, Constance, and Eva after the concert and they quickly became friends. Since joining she has gained fame by singing Seelenschmerz, Vampire Romance, Black Roses and Krieger (2014). Goldmann's debut was in The Oxidising Angel.
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Thus, the colour of iron-rich clays can be influenced by controlling the atmosphere during firing, aiming for it to be either "reducing" (i.e. poor in oxygen and rich in carbon) or "oxidising" (i.e. rich in oxygen). This control is the essence of three-phase firing.
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For example, dissolving in a hot, concentrated aqueous solution of potassium hydroxide forms the potassium salt . The anhydrous salts may be synthesized by heating metal oxides or hydroxides with . All plumbate(IV) salts are very strong oxidising agents. Some hydrated plumbate(IV) salts decompose upon dehydration.
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Rastall suggests a variety of reagents to prevent or reduce degradation, such as thiol reagents or phenol to protect tryptophan and tyrosine from attack by chlorine, and pre-oxidising cysteine. He also suggests measuring the quantity of ammonia evolved to determine the extent of amide hydrolysis.
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The hexaperchloratoaluminate ion is a triple negative complex of perchlorate with aluminium. It is related to hexanitratoaluminate and tetraperchloratoaluminate all of which are highly oxidising energetic materials. Solid materials that have been produced in this series of hexaperchloratoaluminate salts are lithium hexaperchloratoaluminate, ammoniumhexaperchloratoaluminate, tetramethylammonium hexaperchloratoaluminate, and trinitroniumhexaperchloratoaluminate .
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Alcian blue is an eye and respiratory tract irritant. Solid Alcian blue is a combustible powder and should never be handled close to heat or a naked flame. Heating Alcian blue produces toxic fumes of nitrogen compounds. It can react violently if mixed with oxidising materials.
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Because the process requires vicinal diols, periodate oxidation is often used to selectively label the 3′-termini of RNA (ribose has vicinal diols) instead of DNA as deoxyribose does not have vicinal diols. Periodic acid is also used in as an oxidising agent of moderate strength.
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Potassium dichromate is an oxidising agent in organic chemistry, and is milder than potassium permanganate. It is used to oxidize alcohols. It converts primary alcohols into aldehydes and, under more forcing conditions, into carboxylic acids. In contrast, potassium permanganate tends to give carboxylic acids as the sole products.
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As kainosymmetric orbitals appear in the even rows (except for 1s), this creates an even–odd difference between periods from period 2 onwards: elements in even periods are smaller and have more oxidising higher oxidation states (if they exist), whereas elements in odd periods differ in the opposite direction.
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Oxygen is a strong oxidising agent (O2 \+ 4e → 2H2O = 1.23 V at pH 0). Metal oxides are largely ionic in nature.Moeller 1952, p. 208 Sulfur Sulfur is a bright-yellow moderately reactive solid. It has a density of 2.07 g/cm3 and is soft (MH 2.0) and brittle.
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Subsequently, a polymer network is formed to immobilize the chelated cations in a gel or resin. This is most often achieved by poly-esterification using ethylene glycol. The resulting polymer is then combusted under oxidising conditions to remove organic content and yield a product oxide with homogeneously dispersed cations.
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Potassium perruthenate can also be produced by oxidising potassium ruthenate, K2RuO4, with chlorine gas. The perruthenate ion is unstable and is reduced by water to form the orange ruthenate. Potassium ruthenate may be synthesized by reacting ruthenium metal with molten potassium hydroxide and potassium nitrate.Greenwood and Earnshaw, p.
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The attached cells take advantage of the nutrients and soluble manganous ions attracted to the solid–liquid interface, which are continually replenished by the water flow (Sly et al., 1988a). Mn oxidising bacteria in biofilms have been shown to greatly enhance the rate of Mn oxidation (Sly et al., 1988b).
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Environmental sensors would monitor environmental conditions at the landing site. Various instruments would have measured UV rays, oxidising substances, air pressure, air temperature, dust impact, wind velocity, and ground vibration. These sensors would have a combined mass of 130 g. Flight models were previously developed for Britain's Beagle 2 lander.
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Nitric acid is used as the oxidising agent. Blue, green and violet rings are seen if bilirubin is present. Gmelin's test is not sensitive so a positive result always indicates the presence of bile pigments but a negative result does not exclude the presence of small quantities of bile pigments.
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The process involved the melting of pig iron in an oxidising atmosphere. The metal was then allowed to cool, broken up by stamping, and washed. The granulated iron was then heated in pots in a reverberatory furnace. The resultant bloom was then drawn out under a forge hammer in the usual way.
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Ferrate(VI) is an inorganic anion of chemical formula [FeO4]2−. It is photosensitive and contributes a pale violet colour to its compounds and solutions. It is one of the strongest water-stable oxidising species known. Although it is classified as a weak base, concentrated solutions of ferrate(VI) are only stable at high pH.
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In particular, compounds like Li3AmO4 and Li6AmO6 are comparable to uranates and the ion AmO22+ is comparable to the uranyl ion, UO22+. Such compounds can be prepared by oxidation of Am(III) in dilute nitric acid with ammonium persulfate. Other oxidising agents that have been used include silver(I) oxide, ozone and sodium persulfate.
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In oxidations of alcohols or aldehydes into carboxylic acids, chromic acid is one of several reagents, including several that are catalytic. For example, nickel(II) salts catalyze oxidations by bleach (hypochlorite). Aldehydes are relatively easily oxidised to carboxylic acids, and mild oxidising agents are sufficient. Silver(I) compounds have been used for this purpose.
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This can be done by conducting the reaction in the presence of an oxidising agent that oxidises HI to I2, thus removing HI from the reaction and generating more iodine that can further react. The reaction steps involved in iodination are the following: 400x400px Another method to obtain aromatic iodides is the Sandmeyer reaction.
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Organic peroxides are often industrially used as oxidising agents. Exposure to such agents, for instance in the reported case of humans that were exposed to methyl ethyl ketone peroxide (MEKP), has been shown to cause peripheral zonal necrosis, increased hepatic enzyme levels and atypical pseudo-ductular proliferation at doses between 50 and 100 mL.
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These chemicals are more resistant to atmospheric oxidising agents than silver. If colour negative film is processed in conventional black and white developer, and fixed and then bleached with a bath containing hydrochloric acid and potassium dichromate solution, the resultant film, once exposed to light, can be redeveloped in colour developer to produce an unusual pastel colour effect.
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117, 214–21 The vermicast is incorporated into the media substrate, slowly increasing its volume. As this builds up it can be removed and applied to soil as an amendment to improve soil fertility and structure. Microorganisms present are heterotrophic and autotrophic. Heterotrophic microorganisms are important in oxidising carbon (decomposition) whereas autotrophic microorganisms are important in nitrification.
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Almost all amine oxides are prepared by the oxidation of either tertiary aliphatic amines or aromatic N-heterocycles. Hydrogen peroxide is the most common reagent both industrially and in academia, however peracids are also important. More specialised oxidising agents can see niche use, for instance Caro's acid or mCPBA. Spontaneous or catalysed reactions using molecular oxygen are rare.
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The Manhattan Project required the production and handling of uranium hexafluoride for uranium enrichment, whether by diffusion or centrifuge. Uranium hexafluoride is very corrosive, oxidising, volatile solid (sublimes at 56 °C).Uranium Hexafluoride , International Chemical Safety Cards #1250. To handle this material, several new materials were required, including a coolant liquid that could survive contact with uranium hexafluoride.
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In the Fétizon oxidation, silver carbonate on celite serves as an oxidising agent to form lactones from diols. It is also employed to convert alkyl bromides into alcohols. As a base, it has been used in the Wittig reaction.Jedinak, Lukas et al. “Use of Silver Carbonate in the Wittig Reaction.” The Journal of Organic Chemistry 78.23 (2013): 12224–12228.
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It is a poor oxidising agent (Ge + 4e → GeH4 = –0.294 at pH 0). As a metalloid the chemistry of germanium is largely covalent in nature, noting it can form alloys with metals such as aluminium and gold. Most alloys of germanium with metals lack metallic or semimetallic conductivity. The common oxide of germanium (GeO2) is amphoteric.
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As a strong acid, HMnO4 is deprotonated to form the intensely purple coloured permanganates. Potassium permanganate, KMnO4, is a widely used, versatile and powerful oxidising agent. Permanganic acid solutions are unstable, and gradually decompose into manganese dioxide, oxygen, and water, with initially formed manganese dioxide catalyzing further decomposition. Decomposition is accelerated by heat, light, and acids.
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The salts were made by oxidising nickel sulfate mixed with potassium periodate (or sodium periodate) with the alkali persulfate salt in boiling water. Similar solids exist for other alkalis such as RbNiIO6·0.5H2O ,CsNiIO6·0.5H2O and NH4NiIO6·0.5H2O. The crystalline salts are insoluble in water, acids or bases. Ozone can also be used as the oxidiser.
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There are several ways to produce substituted borinic acids. Firstly borinic acids can be made from oxidising trialkyl borane starting materials [R3B] with exposure to moist air, or treatment with iodine, which makes a dialkyliodoborane [R2BI]. Hydrolysis then results in the boronic acid (R2BOH). Trialkylborates [(RO)3B] or trialkoxyboroxine [(ROBO)3] can be reduced to borinic acid by us of a Grignard reagent.
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It is not necessary but highly likely that this kindling phase took place in an oxidising atmosphere: an oxygen-rich fire is likely in any case, since it is much more effective in producing heat. Further, the fact that reducing fires are extremely smoky would probably have been considered undesirable, and they were thus limited to the relatively short 2nd phase.
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Potassium nitrate and potassium permanganate are often used as powerful oxidising agents. Potassium superoxide is used in breathing masks, as it reacts with carbon dioxide to give potassium carbonate and oxygen gas. Pure potassium metal is not often used, but its alloys with sodium may substitute for pure sodium in fast breeder nuclear reactors. Rubidium and caesium are often used in atomic clocks.
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Supercritical water oxidation uses supercritical water as a medium in which to oxidize hazardous waste, eliminating production of toxic combustion products that burning can produce. The waste product to be oxidised is dissolved in the supercritical water along with molecular oxygen (or an oxidising agent that gives up oxygen upon decomposition, e.g. hydrogen peroxide) at which point the oxidation reaction occurs.
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It has a high ionisation energy (1086.5 kJ/mol), moderate electron affinity (122 kJ/mol), and high electronegativity (2.55). Carbon is a poor oxidising agent (C + 4e− → CH4 = 0.13 V at pH 0). Its chemistry is largely covalent in nature, noting it can form salt-like carbides with highly electropositive metals. The common oxide of carbon (CO2) is a medium-strength acidic oxide.
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It has a rhombohedral polyatomic crystalline structure (CN 3). Arsenic is a semimetal, with an electrical conductivity of around 3.9 × 104 S•cm−1 and a band overlap of 0.5 eV. It has a moderate ionisation energy (947 kJ/mol), moderate electron affinity (79 kJ/mol), and moderate electronegativity (2.18). Arsenic is a poor oxidising agent (As + 3e → AsH3 = –0.22 at pH 0).
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This is higher than selenium but lower than boron, the least electrically conducting of the recognised metalloids. Iodine is an insulator in the direction perpendicular to its planes. It has a high ionisation energy (1008.4 kJ/mol), high electron affinity (295 kJ/mol), and high electronegativity (2.66). Iodine is a moderately strong oxidising agent (I2 \+ 2e → 2I− = 0.53 V at pH 0).
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TiH1.95 is unaffected by water and air. It is slowly attacked by strong acids and is degraded by hydrofluoric and hot sulfuric acids. It reacts rapidly with oxidising agents, this reactivity leading to the use of titanium hydride in pyrotechnics. The material has been used to produce highly pure hydrogen, which is released upon heating the solid starting at 300 °C.
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In the ecological restoration industry it is used in the treatment of soils. Calcium peroxide is used in a similar manner to magnesium peroxide for environmental restoration programs. It is used to restore soil and groundwater contaminated with petroleum by the process of enhanced in-situ bioremediation. It is also used for curing polythioether polymers by oxidising terminal thiol groups to disulphide bridges.
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Although dibromine is a strong oxidising agent with a high first ionisation energy, very strong oxidisers such as peroxydisulfuryl fluoride (S2O6F2) can oxidise it to form the cherry-red cation. A few other bromine cations are known, namely the brown and dark brown .Greenwood and Earnshaw, pp. 842–4 The tribromide anion, , has also been characterised; it is analogous to triiodide.
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This could be loaded through a shaft and then set on fire through an opening on the ground. This opening enabled a continuous supply of oxygen, which could be used to create an oxidising atmosphere. The oven now had to reach a set firing temperature in order to heat the clay in the firing chamber. As a result, the fire lasted longer and burnt more consistently.
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An example is the Apollo 13 mission, during which the lunar module pilot experienced an acute urinary tract infection which required two weeks of antibiotic therapy to resolve. Biofilm that may contain a mixture of bacteria and fungi have the potential to damage electronic equipment by oxidising various components e.g. copper cables. Such organisms flourish because they survive on the organic matter released from the astronaut's skin.
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Vanadium(IV) oxide or vanadium dioxide is an inorganic compound with the formula VO2. It is a dark blue solid. Vanadium(IV) dioxide is amphoteric, dissolving in non-oxidising acids to give the blue vanadyl ion, [VO]2+ and in alkali to give the brown [V4O9]2− ion, or at high pH [VO4]4−. VO2 has a phase transition very close to room temperature (~66 °C).
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Round about October the tree produces a spectacular flush of bright red new leaves, flowering taking place at the same time and adding a purple hue. Slashed bark oozes watery, clear or amber-coloured sap with a musky smell. The cut surface is initially white, but turns purplish after oxidising. Young leaves have long linear stipules which are soon shed, and are absent on some trees.
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It is prepared by oxidising selenium compounds in lower oxidation states. One method involves the oxidation of selenium dioxide with hydrogen peroxide: : + → . Unlike the production sulfuric acid by hydration of sulfur trioxide, the hydration of selenium trioxide is an impractical method. Instead, selenic acid may also be prepared by the oxidation of selenous acid () with halogens, such as chlorine or bromine, or with potassium permanganate.
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Selenium has a hexagonal polyatomic (CN 2) crystalline structure. It is a semiconductor with a band gap of 1.7 eV, and a photoconductor meaning its electrical conductivity increases a million-fold when illuminated. Selenium has a moderate ionisation energy (941.0 kJ/mol), high electron affinity (195 kJ/mol), and high electronegativity (2.55). It is a poor oxidising agent (Se + 2e− → H2Se = −0.082 V at pH 0).
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Tellurium has a moderate ionisation energy (869.3 kJ/mol), high electron affinity (190 kJ/mol), and moderate electronegativity (2.1). It is a poor oxidising agent (Te + 2e− → H2Te = −0.45 V at pH 0). The chemistry of tellurium is largely covalent in nature, noting it has an extensive organometallic chemistry and that many tellurides can be regarded as metallic alloys. The common oxide of tellurium (TeO2) is amphoteric.
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Elemental bromine is toxic and causes chemical burns on human flesh. Inhaling bromine gas results in similar irritation of the respiratory tract, causing coughing, choking, and shortness of breath, and death if inhaled in large enough amounts. Chronic exposure may lead to frequent bronchial infections and a general deterioration of health. As a strong oxidising agent, bromine is incompatible with most organic and inorganic compounds.
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Bread improvers and dough conditioners are often used in producing commercial breads to reduce the time needed for rising and to improve texture and volume. The substances used may be oxidising agents to strengthen the dough or reducing agents to develop gluten and reduce mixing time, emulsifiers to strengthen the dough or to provide other properties such as making slicing easier, or enzymes to increase gas production.
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Ammonium dichromate is a strong oxidising agent and reacts, often violently, with any reducing agent. The stronger the reducing agent, the more violent the reaction. It has also been used to promote the oxidation of alcohols and thiols. Ammonium dichromate, in the presence of Mg(HSO4)2 and wet SiO2 can act as a very efficient reagent for the oxidative coupling of thiols under solvent free conditions.
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Cornice and base mouldings were kept to a minimal in an endeavour to avoid dust being carried through the ventilation system. A Montgomerie Neilsen oxidising non-septic toilet system was installed with a large brick tank under the building. This basement was accessed from the rear of the building. Inside the building the toilets were located at the rear of the office on both levels.
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The anion is generated by dissolving in hot concentrated HNO3. The salt consists of the anion and a pair of NH4+ counter ions. The ammonium ions are not involved in the oxidising reactions of this salt. In the anion each nitrate group is chelated to the cerium atom in a bidentate manner as shown below: :Hexanitratocerate anion The anion has Th (idealized Oh) molecular symmetry.
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However, if individuals with CGD are infected with catalase-positive bacteria, the bacterial catalase can destroy the excess peroxide before it can be used to produce other oxidising substances. In these individuals the pathogen survives and becomes a chronic infection. This chronic infection is typically surrounded by macrophages in an attempt to isolate the infection. This wall of macrophages surrounding a pathogen is called a granuloma.
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The word was introduced as a colour term about the same time as "mauve" and "magenta", but it has not survived in the English language. The dye is made from phenol, first oxidising it with oxalic acid and sulfuric acid to make a red substance called rosolic acid. By treating this with ammonia, a dye called red coralline or péonine was made. When reacted with aniline, the blue azuline was produced.
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Due to the elimination of metallic contact and adhesion by the generation of oxide, friction and wear is reduced. Effectively, such a surface is self- lubricating. As the "glaze" is already an oxide, it can survive to very high temperatures in air or oxidising environments. However, it is disadvantaged by it being necessary for the base metal (or ceramic) having to undergo some wear first to generate sufficient oxide debris.
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An electro-chemical oxidation process. The organic waste is treated by the generation of highly oxidising species in an electro-chemical cell. The cell is separated into two compartments by a membrane that allows ion flow but prevents bulk mixing of the anolyte and catholyte. In the anolyte compartment a highly reactive species of silver ion attacks organic material ultimately converting it to CO2, H2O and non-toxic inorganic compounds.
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The relative reducing and oxidizing natures of these photocatalysts can be understood by considering the ligands' electronegativity and the catalyst complex's metal center. More electronegative metals and ligands can stabilize electrons better than their less electronegative counterparts. Therefore, complexes with more electronegative ligands are more oxidising than less electronegative ligand complexes. For example, the ligands 2,2'-bipyridine and 2,2'-phenylpyridine are isoelectronic structures, containing the same number and arrangement of electrons.
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Although it is the most stable chlorine oxide, Cl2O7 is a strong oxidizer as well as an explosive that can be set off with flame or mechanical shock, or by contact with iodine. Nevertheless, it is less strongly oxidising than the other chlorine oxides, and does not attack sulfur, phosphorus, or paper when cold. It has the same effects on the human body as elemental chlorine, and requires the same precautions.
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The exposure to these reactive species in the respiratory burst results in pathology. This is due to oxidative damage to the engulfed bacteria. Notably, peroxynitrite is a very strong oxidising agent that can lead to lipid peroxidation, protein oxidation, protein nitration, which are responsible for its bactericidal effects. It may react directly with proteins that contain transition metal centers, such as FeS, releasing Fe2+ for the Fenton reaction.
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It is a poor oxidising agent (Sb + 3e → SbH3 = –0.51 at pH 0). As a metalloid, its chemistry is largely covalent in nature, noting it can form alloys with one or more metals such as aluminium, iron, nickel, copper, zinc, tin, lead and bismuth, and has an extensive organometallic chemistry. Most alloys of antimony with metals have metallic or semimetallic conductivity. The common oxide of antimony (Sb2O3) is amphoteric.
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Fluorine is a powerful oxidising agent (F2 \+ 2e → 2HF = 2.87 V at pH 0); "even water, in the form of steam, will catch fire in an atmosphere of fluorine".Wulfsberg 1987, p. 159 Metal fluorides are generally ionic in nature. Chlorine gas Chlorine is an irritating green-yellow diatomic gas that is extremely reactive, and has a gaseous density of 3.2 × 10−3 g/cm3 (about 2.5 times heavier than air).
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Jian Zhan blackwares, mainly comprising tea wares, were made at kilns located in Jianyang, Fujian province. They reached the peak of their popularity during the Song dynasty. The wares were made using locally won, iron-rich clays and fired in an oxidising atmosphere at temperatures in the region of . The glaze was made using clay similar to that used for forming the body, except fluxed with wood-ash.
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Greenwood and Earnshaw, pp. 800–4 Corresponding to periodic trends, it is intermediate in electronegativity between chlorine and iodine (F: 3.98, Cl: 3.16, Br: 2.96, I: 2.66), and is less reactive than chlorine and more reactive than iodine. It is also a weaker oxidising agent than chlorine, but a stronger one than iodine. Conversely, the bromide ion is a weaker reducing agent than iodide, but a stronger one than chloride.
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The tropylium cation reacts with nucleophiles to form substituted cycloheptatrienes, for example: : + → Reduction by lithium aluminum hydride yields cycloheptatriene. Reaction with a cyclopentadienide salt of sodium or lithium yields 7-cyclopentadienylcyclohepta-1,3,5-triene: : + → + When treated with oxidising agents such as chromic acid, the tropylium cation undergoes rearrangement into benzaldehyde: : + → + + Many metal complexes of tropylium ion are known. One example is [Mo(η7-C7H7)(CO)3]+, which is prepared by hydride abstraction from cycloheptatrienemolybdenum tricarbonyl.
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High-resolution image of the edge of the pool detailing the orpiment and stibnite deposits. Although Champagne Pool is geochemically well characterised, few studies have addressed its role as a potential habitat for microbial life forms. H2 and either CO2 or O2 would be available as metabolic energy sources for autotrophic growth of methanogenic or hydrogen-oxidising microorganisms. Culture-independent methods provided evidence for filamentous, coccoid and rod-shaped cell morphologies in the hot spring.
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The Lemieux–Johnson reaction ceases at the aldehyde stage of oxidation and therefore produces the same results as ozonolysis. :600px The classical Lemieux–Johnson oxidation often generates many side products, resulting in low reaction yields; however the addition of non-nucleophilic bases, such as 2,6-lutidine, can improve on this. OsO4 may be replaced with a number of other Osmium compounds. Periodate may also be replaced with other oxidising agents, such as oxone.
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The β-glycosidic bond between glucose and the hydroxyl group at C5 on the pyrimidine ring are hydrolysed to yield the aglycone of vicine, divicine (2,6-diamino-4,5-dihydroxypyrimidine). These aglycones have a strong oxidising capacity for glutathione. In healthy individuals, this is not a problem, as glutathione can be reduced quickly enough to regenerate it. In individuals with a deficiency for glucose 6-phosphate dehydrogenase (G6PD) however, this results in haemolytic anaemia.
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Sodium periodate is an inorganic salt, composed of a sodium cation and the periodate anion. It may also be regarded as the sodium salt of periodic acid. Like many periodates it can exist in two different forms: sodium metaperiodate, which has the formula NaIO4, and sodium orthoperiodate, normally this means sodium hydrogen periodate (Na2H3IO6) but the fully reacted sodium orthoperiodate salt, Na5IO6, can also be prepared. Both salts are useful oxidising agents.
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Chlorine is a strong oxidising agent (Cl2 \+ 2e → 2HCl = 1.36 V at pH 0). Metal chlorides are largely ionic in nature. The common oxide of chlorine (Cl2O7) is strongly acidic. Liquid bromine Bromine is a deep brown diatomic liquid that is quite reactive, and has a liquid density of 3.1028 g/cm3. It boils at 58.8 °C and solidifies at −7.3 °C to an orange crystalline solid (density 4.05 g/cm−3).
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It is the only element, apart from mercury, known to be a liquid at room temperature. The solid form, like chlorine, has an orthorhombic crystalline structure and is soft and easily crushed. Bromine is an insulator in all of its forms. It has a high ionisation energy (1139.9 kJ/mol), high electron affinity (324 kJ/mol), and high electronegativity (2.96). Bromine is a strong oxidising agent (Br2 \+ 2e → 2HBr = 1.07 V at pH 0).
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Angel Dust was released in 2002, placing 58th on the German Charts. The Angel Dust promotional photo-shoot and booklet was made by Nina Bendigkeit. In 2004 their fourth album, Demon Kiss, was released, featuring the single "Forever". A DVD release Live Lines and the album-length EP The Oxidising Angel appeared in 2005, the latter of which contained new material as well as a cover of "Cry Little Sister" from The Lost Boys soundtrack.
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Sodium perborate is chemical compound whose chemical formula may be written , , or, more properly, ·. Its name is sometimes abbreviated as PBS. The compound is commonly encountered in anhydrous form or as a hexahydrate (commonly called "monohydrate" or PBS-1 and "tetrahydrate" or PBS-4, after the early assumption that would be the anhydrous form).Alexander McKillop and William R Sanderson (1995): "Sodium perborate and sodium percarbonate: Cheap, safe and versatile oxidising agents for organic synthesis".
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A strong room was built behind the banking chamber. It was thought to be the largest in the north and was reinforced with steel railway rails. A Montgomerie Neilsen Oxidising nonseptic toilet system was installed with a large brick tank under the building. The special windows, which appear to be similar to those installed in the Sydney Head Office building, were special Simplex patented steel framed windows which adjusted to any angle.
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Self- rescue respirator, as carried Self-rescue respirator, as worn during use A respirator's function is to protect against carbon monoxide, as the most likely dangerous gas after a mining fire or explosion. The respirator does this by oxidising the toxic monoxide to safe carbon dioxide. The key feature of a respirator is a reactive catalyst bed, of a material like Hopcalite. This is a mixture of copper and manganese oxides, which acts as an oxidiser.
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High process temperatures are required to convert the raw material mix to Portland cement clinker. Kiln charge temperatures in the sintering zone of rotary kilns range at around 1450 °C. To reach these, flame temperatures of about 2000 °C are necessary. For reasons of clinker quality the burning process takes place under oxidising conditions, under which the partial oxidation of the molecular nitrogen in the combustion air resulting in the formation of nitrogen monoxide (NO) dominates.
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Cort added dampers to the chimney, avoiding some of the risk of overheating and 'burning' the iron. Cort's process consisted of stirring molten pig iron in a reverberatory furnace in an oxidising atmosphere, thus decarburising it. When the iron "came to nature", that is, to a pasty consistency, it was gathered into a puddled ball, shingled, and rolled (as described below). This application of grooved rollers to the rolling mill, to roll narrow bars, was also Cort's invention.
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Sulfur is an insulator with a band gap of 2.6 eV, and a photoconductor meaning its electrical conductivity increases a million-fold when illuminated. Sulfur has a moderate ionisation energy (999.6 kJ/mol), moderate electron affinity (200 kJ/mol), and high electronegativity (2.58). It is a poor oxidising agent (S8 \+ 2e− → H2S = 0.14 V at pH 0). The chemistry of sulfur is largely covalent in nature, noting it can form ionic sulfides with highly electropositive metals.
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Chemistry of the Elements (2nd Edn.), Oxford:Butterworth- Heinemann. . Unlike osmium tetroxide, ruthenium tetroxide is less stable and is strong enough as an oxidising agent to oxidise dilute hydrochloric acid and organic solvents like ethanol at room temperature, and is easily reduced to ruthenate () in aqueous alkaline solutions; it decomposes to form the dioxide above 100 °C. Unlike iron but like osmium, ruthenium does not form oxides in its lower +2 and +3 oxidation states.Greenwood and Earnshaw, pp.
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The CH2Cl2 is then evaporated using a vacuum, creating an oil which is then dissolved in a nonaqueous ether. Finally, HCl gas is bubbled through the mixture to produce 4-methylmethcathinone hydrochloride. This method produces a mixture of both enantiomers and requires similar knowledge to that required to synthesise amphetamines and MDMA. Mephedrone synthesis scheme from 4-methylpropiophenone It can also be produced by oxidising the ephedrine analogue 4-methylephedrine using potassium permanganate dissolved in sulfuric acid.
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After a few days, the water is replenished to maintain the bacteria, and some additional flesh may be cut away. Most medium-sized animals (like dogs) are macerated within about ten days. Lipids and fatty acids in the bone and in the fat tissues tend to stain the bone brown. Oxidising bleaches may be used to whiten the bone, but if too much is used the perchlorate or hypochlorite damages the bone tissue, leaving it chalky and brittle.
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Violet iodine vapour in a flask. Iodine is the fourth halogen, being a member of group 17 in the periodic table, below fluorine, chlorine, and bromine; it is the heaviest stable member of its group (the scarce and fugitive fifth halogen, the radioactive astatine, is not well-studied due to its expense and inaccessibility in large quantities, but appears to show various unusual properties due to relativistic effects). Iodine has an electron configuration of [Kr]4d105s25p5, with the seven electrons in the fifth and outermost shell being its valence electrons. Like the other halogens, it is one electron short of a full octet and is hence a strong oxidising agent, reacting with many elements in order to complete its outer shell, although in keeping with periodic trends, it is the weakest oxidising agent among the stable halogens: it has the lowest electronegativity among them, just 2.66 on the Pauling scale (compare fluorine, chlorine, and bromine at 3.98, 3.16, and 2.96 respectively; astatine continues the trend with an electronegativity of 2.2).
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Poly(2,6-diphenylphenylene oxide) is a low bleeding material with a low level of impurities, and has a high thermal stability (up to 350 °C). Before use poly(2,6-diphenylphenylene oxide) should be thermally conditioned with a high purity gas at elevated temperatures to remove any residual components. During conditioning or thermal desorption the presence of oxygen should be avoided. Poly(2,6-diphenylphenylene oxide) reacts with oxidising agents such as chlorine, ozone, nitrogen oxides and sulfur oxides forming acetophenone, benzaldehyde and phenol.
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Chlorine is a chemical element with the symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between them. Chlorine is a yellow-green gas at room temperature. It is an extremely reactive element and a strong oxidising agent: among the elements, it has the highest electron affinity and the third-highest electronegativity on the Pauling scale, behind only oxygen and fluorine.
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As a result of mining activities, groundwater moves towards the excavation cavities. A 220-kilometre (85-square- mile) underground water body that holds over of water has formed in eight abandoned underground mines: Ahtme, Kohtla, Kukruse, Käva, Sompa, Tammiku, No.2 and No.4. The process of pumping water from the mines introduces oxygen via aeration, thereby oxidising the rock's pyrite. Pyrite contains sulfur, and one consequence of its oxidation is the introduction of significant amounts of sulphates into mine water.
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Reston, Va.: U.S. Department of the Interior, U.S. Geological Survey. Ceria has also been used as a substitute for its radioactive congener thoria, for example in the manufacture of electrodes used in gas tungsten arc welding, where ceria as an alloying element improves arc stability and ease of starting while decreasing burn-off. Cerium(IV) sulfate is used as an oxidising agent in quantitative analysis. Cerium(IV) in methanesulfonic acid solutions is applied in industrial scale electrosynthesis as a recyclable oxidant.
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Tetradentate ligands can be neutral, so that the charge of the whole complex is the same as the central atom. A tetradentate monoanionic (TMDA) ligand has one donor atom with a negative charge. A tetradentate dianionic ligand has a double negative charge, and tetradentate trianionic ligands have a triple negative charge. The maximal charge is on tetradentate tetraanionic ligands, which can stabilise metals in high oxidation states, however such ligands also have to resist oxidation to survive a strongly oxidising atom.
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Neutrophils and other phagocytes use peroxide to kill bacteria. The enzyme NADPH oxidase generates superoxide within the phagosome, which is converted via hydrogen peroxide to other oxidising substances like hypochlorous acid which kill phagocytosed pathogens. In individuals with chronic granulomatous disease (CGD) there is a defect in producing peroxide via mutations in phagocyte oxidases such as myeloperoxidase. Normal cellular metabolism will still produce a small amount of peroxide and this peroxide can be used to produce hypochlorous acid to eradicate the bacterial infection.
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During the final phase of firing, the aeration openings of the kiln are reopened: oxidising conditions are restored. Those areas of the vessels that were not sealed in phase 2 now reoxidise: black iron oxide FeO turns back into red hematite Fe2O3.The different surface qualities of sintered/vitrified and unsintered surfaces are clearly depicted in electron microscope photographs in Hofmann (1962). After complete oxidation of the red areas, the kiln could be opened, its contents were then permitted to cool down slowly, and eventually removed.
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Tentatively, there may be examples of syntrophy between acidophilic species, and even cross- domain cooperation between archaea and bacteria. One mutalistic example is the rotation of iron between species; ferrous-oxidising chemolithotrophs use iron as an electron donor, then ferric-reducing heterotrophs use iron as an electron-acceptor. Another more synergistic behaviour is the faster oxidation of ferrous iron when A.ferrooxidans and Sulfobacillus thermosulfidooxidans are combined in low-CO2 culture. S.thermosulfidooxidans is a more efficient iron- oxidiser, but this is usually inhibited by low-CO2 uptake.
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Part of it, which remained in situ, bore the marks of impact from a keg lid. In the immediate vicinity of the spilled AZDN there were bags of sodium persulphate (SPS), an oxidising agent. The internal fire crew brought up an appliance and laid out their hoses, but it was decided to clear up the spillage by means of a vacuum cleaner. At 14:15 hours the shift chemist could see that a reaction was taking place in or near a bag of SPS.
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After decades of neglect, speleology, and in particular the Cantabria University Speleology Club since 1975, have discovered its true geological value. On July 1, 2005 the Government of Cantabria opened it to the public and publicised it internationally, after development for tourism and protection rules prohibiting any further activity by the discoverering club. Research goes on, resulting in the study of amber deposits, the recognition of underground stromatolites formed by manganese-oxidising bacteria, and a new mineral form, zaccagnaite-3R. The cave recently started holding music concerts.
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It can also be prepared by treating bromides with non- oxidising acids like phosphoric or acetic acids. Alternatively the acid can be prepared with dilute (5.8M) sulfuric acid and potassium bromide: :H2SO4 \+ KBr → KHSO4 \+ HBr Using more concentrated sulfuric acid or allowing the reaction solution to exceed 75 °C further oxidizes HBr to bromine gas. The acid is further purified by filtering out the KHSO4 and by distilling off the water until the solution reaches an azeotrope (≈ 126 °C at 760 torr). The yield is approximately 85%.
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During the years, Matas has been forced to stop selling various chemicals since they were being purchased and used to create improvised explosive devices, especially around New Year's Eve. Among these chemicals are potassium nitrate and potassium permanganate, which are both strong oxidising agents. By 2008 potassium permanganate are again being sold in some Matas shops, albeit under a different brand. In 2011 the company was involved in a conflict with the Danish pharmacy industry, as it campaigned for the right to dispense prescription-only medication.
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Rhodocene is ca. 500 mV more reducing than cobaltocene, indicating that it is more readily oxidised and hence less stable. An earlier polarographic investigation of rhodocenium perchlorate at neutral pH showed a cathodic wave peak at −1.53 V (versus SCE) at the dropping mercury electrode, corresponding to the formation rhodocene in solution, but the researchers were unable to isolate the neutral product from solution. In the same study, attempts to detect iridocene by exposing iridocenium salts to oxidising conditions were unsuccessful even at elevated pH.
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Hydrogen is an insulator in all of its forms. It has a high ionisation energy (1312.0 kJ/mol), moderate electron affinity (73 kJ/mol), and moderate electronegativity (2.2). Hydrogen is a poor oxidising agent (H2 \+ 2e− → 2H– = –2.25 V at pH 0). Its chemistry, most of which is based around its tendency to acquire the electron configuration of the noble gas helium, is largely covalent in nature, noting it can form ionic hydrides with highly electropositive metals, and alloy-like hydrides with some transition metals.
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It is a semiconductor with a band gap of 0.3 eV. It has a high ionisation energy (1086.5 kJ/mol), moderate electron affinity (72 kJ/mol), and moderate electronegativity (2.19). In comparison to nitrogen, phosphorus usually forms weak hydrogen bonds, and prefers to form complexes with metals having high electronegativities, large cationic radii, and often low charges (usually +1 or +2. Phosphorus is a poor oxidising agent (P4 \+ 3e− → PH3– = −0.046 V at pH 0 for the white form, −0.088 V for the red).
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Others cluster round deep sea hydrothermal vents where mineral-rich flows of water emerge from the seabed, supporting communities whose primary producers are sulphide-oxidising chemoautotrophic bacteria, and whose consumers include specialised bivalves, sea anemones, barnacles, crabs, worms and fish, often found nowhere else. A dead whale sinking to the bottom of the ocean provides food for an assembly of organisms which similarly rely largely on the actions of sulphur-reducing bacteria. Such places support unique biomes where many new microbes and other lifeforms have been discovered.
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By one account, Cavanaugh was attending a lecture by Meredith L. Jones, curator of worms at the Smithsonian Institution, shortly after she began her graduate studies. Jones was discussing the giant tube worm, a creature lacking both mouth and gut, where the challenge was to understand how it survived. Jones mentioned elemental sulfur crystals within the worms gut; Cavanaugh states that "It was at that point that I jumped up and said, 'Well, it's perfectly clear! They must have sulphur-oxidising bacteria inside their bodies'".
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Disulfide bonds can be formed under oxidising conditions and play an important role in the folding and stability of some proteins, usually proteins secreted to the extracellular medium. Since most cellular compartments are reducing environments, in general, disulfide bonds are unstable in the cytosol, with some exceptions as noted below, unless a sulfhydryl oxidase is present. Cystine is composed of two cysteines linked by a disulfide bond (shown here in its neutral form). Disulfide bonds in proteins are formed between the thiol groups of cysteine residues by the process of oxidative folding.
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By 1960, no compound with a covalently bound noble gas atom had yet been synthesized. The first published report, in June 1962, of a noble gas compound was by Neil Bartlett, who noticed that the highly oxidising compound platinum hexafluoride ionised O2 to . As the ionisation energy of O2 to (1165 kJ mol−1) is nearly equal to the ionisation energy of Xe to Xe+ (1170 kJ mol−1), he tried the reaction of Xe with PtF6. This yielded a crystalline product, xenon hexafluoroplatinate, whose formula was proposed to be .
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The conjugate base of oxalic acid is the hydrogenoxalate anion, and its conjugate base (oxalate) is a competitive inhibitor of the lactate dehydrogenase (LDH) enzyme. LDH catalyses the conversion of pyruvate to lactic acid (end product of the fermentation (anaerobic) process) oxidising the coenzyme NADH to NAD+ and H+ concurrently. Restoring NAD+ levels is essential to the continuation of anaerobic energy metabolism through glycolysis. As cancer cells preferentially use anaerobic metabolism (see Warburg effect) inhibition of LDH has been shown to inhibit tumor formation and growth, thus is an interesting potential course of cancer treatment.
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Thus, the iridium complex transfers an electron to the substrate, causing fragmentation of the substrate and oxidizing the catalyst to the Ir(IV) oxidation state. The oxidized photocatalyst is returned to its original oxidation state by oxidising a reaction additives. Mechanistic diagram of the reductive dehalogenation of unactivated carbon-iodine bonds Like tin-mediated radical dehalogenation reactions, photocatalytic reductive dehalogenation can be used to initiate cascade cyclizations to rapidly generate molecular complexity. In this work, a radical cascade cyclization that closed two five-membered rings and formed two new stereocenters, in good yield.
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Sb2S3 can be prepared from the elements at temperature 500-900 °C: :2Sb + 3S → Sb2S3 Sb2S3 is precipitated when H2S is passed through an acidified solution of Sb(III). This reaction has been used as a gravimetric method for determining antimony, bubbling H2S through a solution of Sb(III) compound in hot HCl deposits an orange form of Sb2S3 which turns black under the reaction conditions.A.I. Vogel, (1951), Quantitative Inorganic analysis, (2d edition), Longmans Green and Co Sb2S3 is readily oxidised, reacting vigorously with oxidising agents. It burns in air with a blue flame.
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Pure alkali metals are dangerously reactive with air and water and must be kept away from heat, fire, oxidising agents, acids, most organic compounds, halocarbons, plastics, and moisture. They also react with carbon dioxide and carbon tetrachloride, so that normal fire extinguishers are counterproductive when used on alkali metal fires. Some Class D dry powder extinguishers designed for metal fires are effective, depriving the fire of oxygen and cooling the alkali metal. Experiments are usually conducted using only small quantities of a few grams in a fume hood.
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In its resting state, the Fe atom (Fe (III)) in the CCP heme is paramagnetic with high spin (S= 5/2). Once the catalytic cycle is initiated, the iron atom is oxidized to form an oxyferryl intermediate (Fe(IV)=O) has low spin (S= 1/2). This is different from most peroxidases, which have the second oxidising equivalent on the porphyrin instead. Compound I of CCP is fairly long-lived, decaying to CCP-compound II with a half-life at room temperature of 40 minutes to a couple hours.
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The Komani area is in the Burgersdorp formation of the Tarkastad sub group, in the upper Beaufort Group Triassic in age in the karoo super group. The lithology is red mudstone 1 to 10 m rich layers and sub-ordinate 1 to 2 m rich sandstone layers deposited by meandering rivers in the flood plain in an oxidising environment gradually filling the Karoo basin. The formation reaches thickness of 600 m in the Komani (Queenstown) and Lady Frere area. Numerous dolerite dykes and ring structures intruded the area creating good localities for ground water exploration.
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Chemically, they tend to have moderate to high ionisation energies, electron affinities, and electronegativity values, and be relatively strong oxidising agents. Collectively, the highest values of these properties are found among oxygen and the nonmetallic halogens. Manifestations of this status include oxygen's major association with the ubiquitous processes of corrosion and combustion, and the intrinsically corrosive nature of the nonmetallic halogens. All five of these nonmetals exhibit a tendency to form predominately ionic compounds with metals whereas the remaining nonmetals tend to form predominately covalent compounds with metals.
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Silicon has a blue-grey metallic lustre. Silicon is a metallic-looking relatively unreactive solid with a density of 2.3290 g/cm3, and is hard (MH 6.5) and brittle. It melts at 1414 °C (cf. steel ~1370 °C) and boils at 3265 °C. Silicon has a diamond cubic structure (CN 4). It is a semiconductor with a band gap of about 1.11 eV. Silicon has a moderate ionisation energy (786.5 kJ/mol), moderate electron affinity (134 kJ/mol), and moderate electronegativity (1.9). It is a poor oxidising agent (Si + 4e → Si4 = –0.147 at pH 0).
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Telluric acid is formed by the oxidation of tellurium or tellurium dioxide with a powerful oxidising agent such as hydrogen peroxide, chromium trioxide or sodium peroxide. :TeO2 \+ H2O2 \+ 2 H2O → Te(OH)6 Crystallization of telluric acid solutions below 10 °C gives Te(OH)6·4H2O. It is oxidizing, as shown by the electrode potential for the reaction below, although it is kinetically slow in its oxidations. :H6TeO6 \+ 2 H+ \+ 2 e− ⇌ TeO2 \+ 4 H2O E ~~o~~ = +1.02 V Chlorine, by comparison, is +1.36 V and selenous acid is +0.74 V in oxidizing conditions.
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Iodometry, known as iodometric titration, is a method of volumetric chemical analysis, a redox titration where the appearance or disappearance of elementary iodine indicates the end point. Note that iodometry involves indirect titration of iodine liberated by reaction with the analyte, whereas iodimetry involves direct titration using iodine as the titrant. Redox titration using sodium thiosulphate, Na2S2O3 (usually) as a reducing agent is known as iodometric titration since it is used specifically to titrate iodine. The iodometric titration is a general method to determine the concentration of an oxidising agent in solution.
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Over 180 kiln sites have been identified extending in historical range from the Song dynasty to the present. From the Ming dynasty, porcelain objects were manufactured that achieved a fusion of glaze and body traditionally referred to as "ivory white" and "milk white". The special characteristic of Dehua porcelain is the very small amount of iron oxide in it, allowing it to be fired in an oxidising atmosphere to a warm white or pale ivory colour. (Wood, 2007) The porcelain body is not very plastic but vessel forms have been made from it.
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Xenon trioxide is a strong oxidising agent and can oxidise most substances that are at all oxidisable. However, it is slow-acting and this reduces its usefulness. Above 25 °C, xenon trioxide is very prone to violent explosion: :2 XeO3 → 2 Xe + 3 O2 (ΔHf = −402 kJ/mol) When it dissolves in water, an acidic solution of xenic acid is formed: :XeO3(aq) + H2O → H2XeO4 H+ \+ This solution is stable at room temperature and lacks the explosive properties of xenon trioxide. It oxidises carboxylic acids quantitatively to carbon dioxide and water.
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It began operation in September 1980. This was used to develop a two-stage process to produce lead bullion from Mount Isa lead concentrate. The first stage was an oxidation step that removed virtually all the sulfur from the feed, oxidising the contained lead to lead oxide (PbO) that was largely collected in the slag (some was carried out of the furnace as lead oxide fume that was returned for lead recovery). The second stage was a reduction step in which the oxygen was removed from the lead to form lead metal.
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He achieved and proved the complete oxidative degradation of Uric Acid with several oxidising agents."Die neue Harnsäurechemie,Tatsachen und Erklärungen"; J. A. Barth, Leipzig, 1936; Heinrich's work was interrupted when he participated in World War I as a reserve officer. After the war he increased his research activities considerably, often in close co-operation with his younger brother Wilhelm Biltz who was also professor of chemistry and with other highly renowned chemists. The German Chemical Industry established in 1925 the Heinrich-Biltz-Foundation which was destined to support highly skilled students.
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These anaerobic bacteria will consume the cellulose as an energy source. Once this commences they create CO2 that is used by other bacteria and thus the cycle begins. Eventually colour layers of different bacteria will appear in the column. At the bottom of the column will be black anaerobic H2S dominated zone with sulfur reducing bacteria, the layer above will be green sulfur photosynthetic anaerobic bacteria, then the layer will be purple which is sulphur anaerobic bacteria, followed by another column of purple anaerobic non-sulfur bacteria and at the top will be a layer of Cyanobacteria which is sulphur oxidising bacteria.
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The high oxidising potential of elemental chlorine led to the development of commercial bleaches and disinfectants, and a reagent for many processes in the chemical industry. Chlorine is used in the manufacture of a wide range of consumer products, about two-thirds of them organic chemicals such as polyvinyl chloride (PVC), many intermediates for the production of plastics, and other end products which do not contain the element. As a common disinfectant, elemental chlorine and chlorine-generating compounds are used more directly in swimming pools to keep them sanitary. Elemental chlorine at high concentration is extremely dangerous, and poisonous to most living organisms.
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Arsenic pentafluoride and antimony pentafluoride form ionic adducts of the form [ClF4]+[MF6]− (M = As, Sb) and water reacts vigorously as follows:Greenwood and Earnshaw, pp. 832–35 :2 H2O + ClF5 ⟶ 4 HF + FClO2 The product, chloryl fluoride, is one of the five known chlorine oxide fluorides. These range from the thermally unstable FClO to the chemically unreactive perchloryl fluoride (FClO3), the other three being FClO2, F3ClO, and F3ClO2. All five behave similarly to the chlorine fluorides, both structurally and chemically, and may act as Lewis acids or bases by gaining or losing fluoride ions respectively or as very strong oxidising and fluorinating agents.
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While not typical of all bacteria some microbes contain intracellular membranes in addition to (or as extensions of) their cytoplasmic membranes. An early idea was that bacteria might contain membrane folds termed mesosomes, but these were later shown to be artifacts produced by the chemicals used to prepare the cells for electron microscopy. Examples of bacteria containing intracellular membranes are phototrophs, nitrifying bacteria and methane-oxidising bacteria. Intracellular membranes are also found in bacteria belonging to the poorly studied Planctomycetes group, although these membranes more closely resemble organellar membranes in eukaryotes and are currently of unknown function.
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Hydrotalcite has been studied as potential getter for iodide in order to scavenge the long-lived 129I (T1/2 = 15.7 million years) and also other fission products such as 79Se (T1/2 = 295 000 years) and 99Tc, (T1/2 = 211 000 years) present in spent nuclear fuel to be disposed under oxidising conditions in volcanic tuff at the Yucca Mountain nuclear waste repository. Carbonate easily replaces iodide in its interlayer. Another difficulty arising in the quest of an iodide getter for radioactive waste is the long-term stability of the sequestrant that must survive over geological time scales.
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Thioploca is a genus of filamentous sulfur bacteria which occurs along of coast off the west of South America. A large vacuole occupies more than 80% of their cell volume and contains sulfide and nitrate which they use to make energy for their metabolism by oxidising sulfide with nitrate. The concentration of nitrate in the vacuole is extremely high (500 mM) even though the sediments in which they live are relatively very low in nitrogen (25 μM). Because they use both sulfur and nitrogen compounds they may provide an important link between the nitrogen and sulfur cycles.
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The older and relatively simple method of cupellation can then be used to separate the silver from the lead. If the lead is assayed and found not to contain enough silver to make the cupellation process worthwhile it is reused in liquation cakes until it has sufficient silver. The ‘exhausted liquation cakes’ which still contain some lead and silver are ‘dried’ in a special furnace which is heated to a higher temperature under oxidising conditions. This is essentially just another stage of liquation and most of the remaining lead is expelled and oxidised to form liquation thorns, though some remains as lead metal.
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Cerium(III) and terbium(III) have ultraviolet absorption bands of relatively high intensity compared with the other lanthanides, as their configurations (one electron more than an empty or half-filled f-subshell respectively) make it easier for the extra f electron to undergo f→d transitions instead of the forbidden f→f transitions of the other lanthanides.Greenwood and Earnshaw, pp. 1242–4 Cerium(III) sulfate is one of the few salts whose solubility in water decreases with rising temperature. Ceric ammonium nitrate Cerium(IV) aqueous solutions may be prepared by reacting cerium(III) solutions with the strong oxidising agents peroxodisulfate or bismuthate.
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The value of E⦵(Ce4+/Ce3+) varies widely depending on conditions due to the relative ease of complexation and hydrolysis with various anions, though +1.72 V is a usually representative value; that for E⦵(Ce3+/Ce) is −2.34 V. Cerium is the only lanthanide which has important aqueous and coordination chemistry in the +4 oxidation state.Greenwood and Earnshaw, pp. 1244–8 Due to ligand-to-metal charge transfer, aqueous cerium(IV) ions are orange-yellow. Aqueous cerium(IV) is metastable in water and is a strong oxidising agent that oxidizes hydrochloric acid to give chlorine gas.
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However, using chlorine or bromine as the oxidising agent also produces hydrochloric or hydrobromic acid as a side-product, which needs to be removed from the solution since they can reduce the selenic acid to selenous acid. Another method of preparing selenic acid is by the oxidation of elemental selenium in a water suspension by chlorine: :Se + 4 + 3 → + 6 HCl To obtain the anhydrous acid as a crystalline solid, the resulting solution is evaporated at temperatures below in a vacuum.Seppelt, K. “Selenoyl difluoride” Inorganic Syntheses, 1980, volume XX, pp. 36-38. . The report describes the synthesis of selenic acid.
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It appears that both the indigenous (San and Khoikhoi) and the colonial inhabitants of rooibos-growing areas contributed to the traditional knowledge of rooibos in some way. For instance, medicinal uses might have been introduced before the eighteenth century, by Khoisan pastoralists or San hunter-gatherers. And the utilisation of the Aspalathus linearis for making tea, including the production processes, such as bruising and oxidising the leaves, are more likely to have been introduced in colonial times, by settlers accustomed to drinking Asian tea or its substitutes. In 1904, Benjamin Ginsberg ran a variety of experiments at Rondegat Farm, finally curing rooibos.
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Perxenic acid and the anion are both strong oxidizing agents, capable of oxidising silver(I) to silver(III), copper(II) to copper(III), and manganese(II) to permanganate. The perxenate anion is unstable in acidic solutions, being almost instantaneously reduced to . The sodium, potassium, and barium salts are soluble. Barium perxenate solution is used as the starting material for the synthesis of xenon tetroxide (XeO4) by mixing it with concentrated sulfuric acid: : Ba2XeO6 (s) + 2 H2SO4 (l) → XeO4 (g) + 2 BaSO4 (s) + 2 H2O (l) Most metal perxenates are stable, except silver perxenate, which decomposes violently.
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However, PSII has an additional function over the bacterial system. At the oxidising side of PSII, a redox-active residue in the D1 protein reduces P680, the oxidised tyrosine then withdrawing electrons from a manganese cluster, which in turn withdraw electrons from water, leading to the splitting of water and the formation of molecular oxygen. PSII thus provides a source of electrons that can be used by photosystem I to produce the reducing power (NADPH) required to convert CO2 to glucose. Instead of assigning specialized roles to quinones, the PsaA-PsaB photosystem I centre evolved to make both quinones immobile.
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Illustrative and secure bromine sample for teaching Bromine is the third halogen, being a nonmetal in group 17 of the periodic table. Its properties are thus similar to those of fluorine, chlorine, and iodine, and tend to be intermediate between those of the two neighbouring halogens, chlorine and iodine. Bromine has the electron configuration [Ar]3d104s24p5, with the seven electrons in the fourth and outermost shell acting as its valence electrons. Like all halogens, it is thus one electron short of a full octet, and is hence a strong oxidising agent, reacting with many elements in order to complete its outer shell.
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The reaction mechanismOrganic chemistry by Jonathan Clayden, Nick Grieves, Stuart Warren, Oxford University Press can be represented as follows: 400x400px Because fluorine is very reactive, the protocol described above would not be efficient as the aromatic molecule would react destructively with F2. Therefore, other methods, such as the Balz–Schiemann reaction, must be used to prepare fluorinated aromatic compounds. For iodine, however, oxidising conditions must be used in order to perform iodination. Because iodination is a reversible process, the products have to be removed from the reaction medium in order to drive the reaction forward, see Le Chatelier's principle.
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The rocket is in development since 2014. The oxidising agent of main engine is highly concentrated H2O2. as researchers from Institute have patented unique method on obtaining this compound by distillation . The project was repeatedly awarded: the jury of International Invention and Innovation Show INTARG 2018 gave the platinium medal in category „Industry” and Ministry of Investment and Economic Development diplomma. On Moscow International Salon of Inventions and Innovation Technologies 2019 Łukasiewicz Research Network – Institute of Aviation has received silver medal for solution: „ILR-33 AMBER rocket as system of inventions and innovative platform to conduct experiments in micro-g environment”.
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The active site of the AOR family feature an oxo-tungsten center bound to a pair of molybdopterin cofactors (which does not contain molybdenum) and an 4Fe-4S cluster. This family includes AOR, formaldehyde ferredoxin oxidoreductase (FOR), glyceraldehyde-3-phosphate ferredoxin oxidoreductase (GAPOR), all isolated from hyperthermophilic archea; carboxylic acid reductase found in clostridia; and hydroxycarboxylate viologen oxidoreductase from Proteus vulgaris, the sole member of the AOR family containing molybdenum. GAPOR may be involved in glycolysis, but the functions of the other proteins are not yet clear. AOR has been proposed to be the primary enzyme responsible for oxidising the aldehydes that are produced by the 2-keto acid oxidoreductases.
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It explodes above −40 °C as a liquid and under pressure as a gas and therefore must be made at low concentrations for wood-pulp bleaching and water treatment. It is usually prepared by reducing a chlorate as follows: : + Cl− \+ 2 H+ ⟶ ClO2 \+ Cl2 \+ H2O Its production is thus intimately linked to the redox reactions of the chlorine oxoacids. It is a strong oxidising agent, reacting with sulfur, phosphorus, phosphorus halides, and potassium borohydride. It dissolves exothermically in water to form dark-green solutions that very slowly decompose in the dark. Crystalline clathrate hydrates ClO2·nH2O (n ≈ 6–10) separate out at low temperatures.
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AZDN kegs were stored in the same section of the warehouse as SPS and other oxidising substances, after being wrongly classified in the documentation. Segregation of Hazardous Materials[1]: Warehouse storage, Incompatible substances Raw Materials Control / Sampling[2]: Safety management systems Failure of the steam heating system or operator error meant that heating was applied in No. 2 oxystore as well as in the main warehouse. Plant Modification / Change Procedures[3]: Decommissioning procedures The oxystores and warehouse were not fitted with adequate smoke detection and fire fighting facilities. Active / Passive Fire Protection[4] The fire brigade and police should have been informed immediately the first incident had been discovered.
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Pulsation reactor technology came to the fore from the nineties through its use in environmental technology, particularly in sludge drying and the regeneration of resin-bonded foundry sands. From 2000 the pulsation reactor was used to produce catalytic powders on an industrial scale. The principle of pulsating combustion was developed over the years by the company IBU-tec advanced materials AG (which emerged from the SKET Institute and still exists today), which finally tested and commissioned another test facility in 2008. Thanks to the continuous optimisation of the reactors, it was now possible to use an oxidising, inert or reducing hot gas atmosphere to treat materials as required.
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The formation of hematitic jasperoids is considered to be the product of highly oxidised metasomatism of the wall rocks to a shear zone. The presence of carbonate alteration, talc-carbonated high-magnesian basalts and ultramafic rocks and the remnant mineralogy being restricted to hematite, silica, and sulfides indicates oxidising fluid chemistry. Relict volcaniclastic textures in some jasperoids indicate that aluminosilicates have been replaced pervasively by silica + hematite. Transitional forms and poorly developed analogs are present in some gold camps within the Yilgarn craton where deep, reduced methane and carbonate bearing alteration fluids mix with shallower oxidised fluids, resulting in purple-pinkish carbonate flooding alteration within basalts and ultramafic rocks.
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PMB ethers are far more susceptible to oxidation than benzyl ethers since they are more electron-rich. The selective deprotection of PMB ethers can be achieved through the use of bis-(2-(2',4'-difluorophenyl)-5-trifluoromethylpyridine)-(4,4'-ditertbutylbipyridine)iridium(III) hexafluorophosphate (Ir[dF(CF3)ppy]2(dtbbpy)PF6) and a mild stoichiometric oxidant such as bromotrichloromethane, BrCCl3. The photoexcited iridium catalyst is reducing enough to fragment the bromotrichloromethane to form a trichloromethyl radical, bromide anion, and the Ir(IV) complex. The electron- poor fluorinated ligands makes the iridium complex oxidising enough to accept an electron from an electron-rich arene such as a PMB ether.
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Beer in the UK is usually served at cellar temperature (between ), which is often controlled in a modern-day pub, although the temperature can naturally fluctuate with the seasons. Proponents of British beer say that it relies on subtler flavours than that of other nations, and these are brought out by serving it at a temperature that would make other beers seem harsh. Where harsher flavours do exist in beer (most notably in those brewed in Yorkshire), these are traditionally mitigated by serving the beer through a hand pump fitted with a sparkler, a device that mixes air with the beer, oxidising it slightly and softening the flavour.
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Copper(II) acetate has found some use as an oxidizing agent in organic syntheses. In the Eglinton reaction Cu2(OAc)4 is used to couple terminal alkynes to give a 1,3-diyne: :Cu2(OAc)4 \+ 2 RC≡CH → 2 CuOAc + RC≡C−C≡CR + 2 HOAc The reaction proceeds via the intermediacy of copper(I) acetylides, which are then oxidized by the copper(II) acetate, releasing the acetylide radical. A related reaction involving copper acetylides is the synthesis of ynamines, terminal alkynes with amine groups using Cu2(OAc)4.. It has been used for hydroamination of acrylonitrile. It is also an oxidising agent in Barfoed's test.
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Only when it is in a positive oxidation state, that is, in combination with oxygen or fluorine, are its compounds good oxidising agents, for example, 2NO3− → N2 = 1.25 V. Its chemistry is largely covalent in nature; anion formation is energetically unfavourable owing to strong inter electron repulsions associated with having three unpaired electrons in its outer valence shell, hence its negative electron affinity. The common oxide of nitrogen (NO) is weakly acidic. Many compounds of nitrogen are less stable than diatomic nitrogen, so nitrogen atoms in compounds seek to recombine if possible and release energy and nitrogen gas in the process, which can be leveraged for explosive purposes.
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Thorium dioxide is used in gas tungsten arc welding (GTAW) to increase the high-temperature strength of tungsten electrodes and improve arc stability. Thorium oxide is being replaced in this use with other oxides, such as those of zirconium, cerium, and lanthanum. Thorium dioxide is found in heat-resistant ceramics, such as high-temperature laboratory crucibles, either as the primary ingredient or as an addition to zirconium dioxide. An alloy of 90% platinum and 10% thorium is an effective catalyst for oxidising ammonia to nitrogen oxides, but this has been replaced by an alloy of 95% platinum and 5% rhodium because of its better mechanical properties and greater durability.
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The site is preserved due to Lake Flixton having been in- filled with peat during the course of the Mesolithic. Waterlogged peat prevents organic finds from oxidising and has led to some of the best preservation conditions possible (such conditions have preserved the famous bog bodies found in other parts of northern Europe). As a result of such good conditions archaeologists were able to recover bone, antler and wood in addition to the flints that are normally all that is left on sites from this period. During the period of Mesolithic occupation the area surrounding the lake would have been a mixed forest of birch, aspen and willow.
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Beryllium iodide can be prepared by reacting beryllium metal with elemental iodine at temperatures of 500 °C to 700 °C: :Be + I2 -> BeI2 Beryllium iodide is also formed when beryllium carbide reacts with hydrogen iodide in the gas phase: :Be2C + 4 HI -> 2 BeI2 \+ CH4 The iodine in beryllium iodide is easily replaced with the other halogens; it reacts with fluorine giving beryllium fluoride and fluorides of iodine, with chlorine giving beryllium chloride, and with bromine giving beryllium bromide. Beryllium iodide also reacts violently with oxidising agents such as chlorate and permanganate to give purple vapour of iodine. The solid and vapor are both flammable in air.
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Flavocytochrome c sulfide dehydrogenase, also known as Sulfide-cytochrome-c reductase (flavocytochrome c) (), is an enzyme with systematic name hydrogen- sulfide:flavocytochrome c oxidoreductase. It is found in sulfur-oxidising bacteria such as the purple phototrophic bacteria Allochromatium vinosum. This enzyme catalyses the following chemical reaction: : hydrogen sulfide + 2 ferricytochrome c \rightleftharpoons sulfur + 2 ferrocytochrome c + 2 H+ These enzymes are heterodimers of a flavoprotein (fccB ) and a dihaem cytochrome (fccA; ) that carry out hydrogen sulfide-dependent cytochrome C reduction. The dihaem cytochrome folds into two domains, each of which resembles mitochondrial cytochrome c, with the two haem groups bound to the interior of the subunit.
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When iodine dissolves in strong acids, such as fuming sulfuric acid, a bright blue paramagnetic solution including cations is formed. A solid salt of the diiodine cation may be obtained by oxidising iodine with antimony pentafluoride: :2 I2 \+ 5 SbF5 2 I2Sb2F11 \+ SbF3 The salt I2Sb2F11 is dark blue, and the blue tantalum analogue I2Ta2F11 is also known. Whereas the I–I bond length in I2 is 267 pm, that in is only 256 pm as the missing electron in the latter has been removed from an antibonding orbital, making the bond stronger and hence shorter. In fluorosulfuric acid solution, deep-blue reversibly dimerises below −60 °C, forming red rectangular diamagnetic .
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From the eighth century to the seventh century BC, the area (Wessex) boasted an elaborate array of different vessel types, often highly decorated and well made. Some were covered with iron oxide and fired in oxidising conditions which produced pottery which could be burnished to shine like bronze vessels. This pottery, which has All Cannings Cross as its typesite, has since been found in an area of southern Britain from the Somerset Levels to eastern Hampshire. This suggests a high degree of interaction during the period and some kind of shared values which indicate that communities in the region were in close contact with another, likely through exchange networks used to trade bronze.
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Rocket propellant is mass that is stored, usually in some form of propellant tank, or within the combustion chamber itself, prior to being ejected from a rocket engine in the form of a fluid jet to produce thrust. Chemical rocket propellants are most commonly used, which undergo exothermic chemical reactions which produce hot gas which is used by a rocket for propulsive purposes. Alternatively, a chemically inert reaction mass can be heated using a high-energy power source via a heat exchanger, and then no combustion chamber is used. Solid rocket propellants are prepared as a mixture of fuel and oxidising components called 'grain' and the propellant storage casing effectively becomes the combustion chamber.
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It may be enclosed, wire-netted or covered to keep out surface animals. Spent soil or compost, and organic amendments such as biochar may be added, as may non-fermented material, in which case the boundary between bokashi and composting becomes blurred. A proposed alternative is to homogenise (and potentially dilute) the preserve into a slurry, which is spread on the soil surface. This approach requires energy for homogenisation but, logically from the characteristics set out above, should confer several advantages: thoroughly oxidising the preserve; disturbing no deeper layers, except by increased worm action; being of little use to scavenging animals; applicable to large areas; and, if done repeatedly, able to sustain a more extensive soil ecosystem.
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Arsenic makes arsenic acid with concentrated nitric acid, arsenous acid with dilute nitric acid, and arsenic trioxide with concentrated sulfuric acid; however, it does not react with water, alkalis, or non-oxidising acids. Arsenic reacts with metals to form arsenides, though these are not ionic compounds containing the As3− ion as the formation of such an anion would be highly endothermic and even the group 1 arsenides have properties of intermetallic compounds. Like germanium, selenium, and bromine, which like arsenic succeed the 3d transition series, arsenic is much less stable in the group oxidation state of +5 than its vertical neighbors phosphorus and antimony, and hence arsenic pentoxide and arsenic acid are potent oxidizers.
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Under controlled conditions, however, all the alkali metals, with the exception of francium, are known to form their oxides, peroxides, and superoxides. The alkali metal peroxides and superoxides are powerful oxidising agents. Sodium peroxide and potassium superoxide react with carbon dioxide to form the alkali metal carbonate and oxygen gas, which allows them to be used in submarine air purifiers; the presence of water vapour, naturally present in breath, makes the removal of carbon dioxide by potassium superoxide even more efficient. All the stable alkali metals except lithium can form red ozonides (MO3) through low-temperature reaction of the powdered anhydrous hydroxide with ozone: the ozonides may be then extracted using liquid ammonia.
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Since the iodide ion is a mild reducing agent, is easily oxidised to by powerful oxidising agents such as chlorine: : This reaction is employed in the isolation of iodine from natural sources. Air will oxidize iodide, as evidenced by the observation of a purple extract when aged samples of KI are rinsed with dichloromethane. As formed under acidic conditions, hydriodic acid (HI) is a stronger reducing agent.N. N. Greenwood, A. Earnshaw, Chemistry of the Elements, Pergamon Press, Oxford, UK, 1984Handbook of Chemistry and Physics, 71st edition, CRC Press, Ann Arbor, Michigan, 1990The Merck Index, 7th edition, Merck & Co., Rahway, New Jersey, 1960 Like other iodide salts, forms when combined with elemental iodine.
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Under very oxidising or very reducing conditions, the steady-state catalytic current sometimes tends to a limiting value (a plateau) which (still provided there is no mass transport limitation) relates to the activity of the fully oxidised or fully reduced enzyme, respectively. If interfacial electron transfer is slow and if there is a distribution of electron transfer rates (resulting from a distribution of orientations of the enzymes molecules on the electrode), the current keeps increasing linearly with potential instead of reaching a plateau; in that case the limiting slope is proportional to the turnover rate of the fully oxidised or fully reduced enzyme. The change in steady-state current against potential is often complex (e.g. not merely sigmoidal).
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Tetrafluoroammonium salts are prepared by oxidising nitrogen trifluoride with fluorine in the presence of a strong Lewis acid which acts as a fluoride ion acceptor. The original synthesis by Tolberg, Rewick, Stringham, and Hill in 1966 employs antimony pentafluoride as the Lewis acid: : + + → The hexafluoroarsenate salt was also prepared by a similar reaction with arsenic pentafluoride at 120 °C: : + + → The reaction of nitrogen trifluoride with fluorine and boron trifluoride at 800 °C yields the tetrafluoroborate salt: : + + → salts can also be prepared by fluorination of with krypton difluoride () and fluorides of the form , where M is Sb, Nb, Pt, Ti, or B. For example, reaction of with and yields . Many tetrafluoroammonium salts can be prepared with metathesis reactions.
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Producing a strong clear yellow could be difficult in early stained glass as it relied upon the careful control of furnace conditions in order to create the appropriate reducing or oxidising environment.Royce-Roll 1994, 74 The introduction of silver stain in the early 14th century not only provided a solution to this difficulty, but also allowed greater flexibility in the way in which colour could be used. The first datable example of the use of silver stain is in the parish church of Le Mesnil-Villeman, Manche, France (1313).Marks 1993, 38 Silver stain was a combination of silver nitrate or silver sulphide blended with pipe clay and applied to (usually) clear glass.
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These include acid rain where sulfur dioxide in the airshed is dissolved in rainfall to produce sulfurous acid. In lightning storms, the dioxide is oxidised to trioxide making the residual sulfuric acid in rainfall even more highly acidic. Local government infrastructure is most commonly corroded by sulfate arising from the oxidation of sulfide which occurs when bacteria (for example in sewer mains) reduce the ever-present hydrogen sulfide gas to a film of sulfide (S-) or bi-sulfide (HS-) ions. This reaction is reversible, both readily oxidising on exposure to air or oxygenated stormwater, to produce sulfite or sulfate ions and acidic hydrogen ions in the reaction HS− \+ H2O+ O2 -> 2H+ \+ SO4-.
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Nitrous oxide is a strong oxidising agent, roughly equivalent to hydrogen peroxide, and much stronger than oxygen gas. Nitrous oxide is stored as a compressed liquid; the evaporation and expansion of liquid nitrous oxide in the intake manifold causes a large drop in intake charge temperature, resulting in a denser charge, further allowing more air/fuel mixture to enter the cylinder. Sometimes nitrous oxide is injected into (or prior to) the intake manifold, whereas other systems directly inject, right before the cylinder (direct port injection) to increase power. The technique was used during World War II by Luftwaffe aircraft with the GM-1 system to boost the power output of aircraft engines.
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In physiology, respiration is the movement of oxygen from the outside environment to the cells within tissues, and the transport of carbon dioxide in the opposite direction. The physiological definition of respiration differs from the biochemical definition, which refers to a metabolic process by which an organism obtains energy (in the form of ATP and NADPH) by oxidising nutrients and releasing waste products. Although physiologic respiration is necessary to sustain cellular respiration and thus life in animals, the processes are distinct: cellular respiration takes place in individual cells of the organism, while physiologic respiration concerns the diffusion and transport of metabolites between the organism and the external environment. In animals with lungs, physiological respiration involves respiratory cycles of inhaled and exhaled breaths.
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Photocatalyst activity indicator inks (Paii's) are a recent advance in the visual demonstration of photocatalysis and the assessment of the activity of photocatalyst materials. They are an inexpensive, easy to use and provide a very quick route to demonstrating the presence of a photocatalytic film, even under low levels of UV light. Unlike the photo-oxidative bleaching of methylene blue, they use the underlying semiconductor photocatalyst film to photoreduce the dye (Dox in figure 2), in the ink coating, to another (usually colourless) form, (Dred in figure 2) whilst simultaneously oxidising an easily oxidised organic species, a sacrificial electron donor (SED), such as glycerol, which is also present in the ink. The kinetics of reduction of the dye in a paii have been studied in great detail.
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The very loosely defined "species" Thiobacillus trautweinii was where sulfur oxidising heterotrophs and chemolithoheterotrophs were assigned in the 1910-1960s era, most of which were probably Pseudomonas species. Many species named in this genus were never deposited in service collections and have been lost. All species are obligate autotrophs (using the transaldolase form of the Calvin-Benson-Bassham cycle) using elementary sulfur, thiosulfate, or polythionates as energy sources - the former Thiobacillus aquaesulis can grow weakly on complex media as a heterotroph, but has been reclassified to Annwoodia aquaesulis. Some strains (E6 and Tk-m) of the type species Thiobacillus thioparus can use the sulfur from dimethylsulfide, dimethyldisulfide, or carbon disulfide to support autotrophic growth - they oxidise the carbon from these species into carbon dioxide and assimilate it.
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ER oxidoreductin 1 (Ero1) is an oxidoreductase enzyme that catalyses the formation and isomerization of protein disulfide bonds in the endoplasmic reticulum (ER) of eukaryotes. ER Oxidoreductin 1 (Ero1) is a conserved, luminal, glycoprotein that is tightly associated with the ER membrane, and is essential for the oxidation of protein dithiols. Since disulfide bond formation is an oxidative process, the major pathway of its catalysis has evolved to utilise oxidoreductases, which become reduced during the thiol- disulfide exchange reactions that oxidise the cysteine thiol groups of nascent polypeptides. Ero1 is required for the introduction of oxidising equivalents into the ER and their direct transfer to protein disulfide isomerase (PDI), thereby ensuring the correct folding and assembly of proteins that contain disulfide bonds in their native state.
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The mechanism of thiol–disulfide exchange between oxidoreductases is understood to begin with the nucleophilic attack on the sulfur atoms of a disulfide bond in the oxidised partner, by a thiolate anion derived from a reactive cysteine in a reduced partner. This generates mixed disulfide intermediates, and is followed by a second, this time intramolecular, nucleophilic attack by the remaining thiolate anion in the formerly reduced partner, to liberate both oxidoreductases. The balance of evidence discussed thus far supports a model in which oxidising equivalents are sequentially transferred from Ero1 via a thiol–disulfide exchange reaction to PDI, with PDI then undergoing a thiol–disulfide exchange with the nascent polypeptide, thereby enabling the formation of disulfide bonds within the nascent polypeptide.
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Consequently it is a strong Lewis acid and reacts with any Lewis base, L to form an adduct. :BH3 \+ L → L—BH3 in which the base donates its lone pair, forming a dative covalent bond. Such compounds are thermodynamically stable, but may be easily oxidised in air. Solutions containing borane dimethylsulfide and borane–tetrahydrofuran are commercially available; in tetrahydrofuran a stabilising agent is added to prevent the THF from oxidising the borane.Hydrocarbon Chemistry, George A. Olah, Arpad Molner, 2d edition, 2003, Wiley-Blackwell A stability sequence for several common adducts of borane, estimated from spectroscopic and thermochemical data, is as follows: :PF3 < CO < Et2O < Me2O < C4H8O < C4H8S < Et2S < Me2S < Py < Me3N < H− BH3 has some soft acid characteristics as sulfur donors form more stable complexes than do oxygen donors.
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Construction of wind farms by the electrical generating industry lead to duplication of existing power plants which were still needed as backup without increasing the utilities customer base or their output.Evans, Richard (4 May 2013) Experts warn of threat to utility shares' income The Telegraph, Retrieved 7 May 2013 Scottish Natural Heritage has stated that the decommissioning of ageing turbine structures in the future would be more deleterious to the environment than leaving the bases in place, thus littering Scotland's wild land with concrete which though they could be covered with topsoil, could lead to "oxidising and subsequent staining/contamination" and would lead to irreversible damage to the sensitive peatlands on which many are built. Alternatively, new wind farms could be built on the same site, minimising overall damage.
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Structure of the oxidising agent 2-iodoxybenzoic acid Organoiodine compounds have been fundamental in the development of organic synthesis, such as in the Hofmann elimination of amines, the Williamson ether synthesis, (Link to excerpt.) the Wurtz coupling reaction, and in Grignard reagents. The carbon–iodine bond is a common functional group that forms part of core organic chemistry; formally, these compounds may be thought of as organic derivatives of the iodide anion. The simplest organoiodine compounds, alkyl iodides, may be synthesised by the reaction of alcohols with phosphorus triiodide; these may then be used in nucleophilic substitution reactions, or for preparing Grignard reagents. The C–I bond is the weakest of all the carbon–halogen bonds due to the minuscule difference in electronegativity between carbon (2.55) and iodine (2.66).
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They gave rise to primitive organisms (cells), which he called coacervates. In his original theory, Oparin considered oxygen as one of the primordial gases; thus the primordial atmosphere was an oxidising one. However, when he elaborated his theory in 1936 (in a book by the same title, and translated into English in 1938), he modified the chemical composition of the primordial environment as strictly reducing, consisting of methane, ammonia, free hydrogen and water vapour—excluding oxygen. In his 1936 work, impregnated by a Darwinian thought that involved a slow and gradual evolution from the simple to the complex, Oparin proposed a heterotrophic origin, result of a long process of chemical and pre-biological evolution, where the first forms of life should have been microorganisms dependent on the molecules and organic substances present in their external environment.
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Anhydrous nitric acid may be made by distilling concentrated nitric acid with phosphorus pentoxide at low pressure in glass apparatus in the dark. It can only be made in the solid state, because upon melting it spontaneously decomposes to nitrogen dioxide, and liquid nitric acid undergoes self-ionisation to a larger extent than any other covalent liquid as follows: :2 HNO3 \+ H2O + [NO2]+ \+ [NO3]− Two hydrates, HNO3·H2O and HNO3·3H2O, are known that can be crystallised. It is a strong acid and concentrated solutions are strong oxidising agents, though gold, platinum, rhodium, and iridium are immune to attack. A 3:1 mixture of concentrated hydrochloric acid and nitric acid, called aqua regia, is still stronger and successfully dissolves gold and platinum, because free chlorine and nitrosyl chloride are formed and chloride anions can form strong complexes.
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Spatial separation of RnF2 molecules may be necessary to clearly identify higher fluorides of radon, of which RnF4 is expected to be more stable than RnF6 due to spin–orbit splitting of the 6p shell of radon (RnIV would have a closed-shell 6s6p configuration). Krypton hexafluoride () has been predicted to be stable, but has not been synthesised due to the extreme difficulty of oxidising krypton beyond Kr(II). The synthesis of americium hexafluoride () by the fluorination of americium(IV) fluoride () was attempted in 1990, but was unsuccessful; there have also been possible thermochromatographic identifications of it and curium hexafluoride (CmF6), but it is debated if these are conclusive. Palladium hexafluoride (), the lighter homologue of platinum hexafluoride, has been calculated to be stable, but has not yet been produced; the possibility of silver (AgF6) and gold hexafluorides (AuF6) has also been discussed.
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Population of Kiwa around a hydrothermal vent Based on the presence of sulphur-oxidising bacteria on the setae of both K. hirsuta and the new South West Indian Ridge species, they may both feed on bacteria in addition to scavenging. For K. puravida, the bacteria have been identified and the feeding behaviour observed, as well as a cyclical rhythmic motion of the crab documented that is suspected to increase the flow of methane and sulfide, the bacterial food, towards the bacteria. The two sexes of the new South West Indian Ridge species prefer different temperatures, with males seeming to prefer warmer water and egg-carrying females and juveniles preferring the coldest. The genus Kiwa is named after "the goddess of the shellfish in the Polynesian mythology", although Kiwa is a male guardian of the sea in Maori mythology.
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Inherent colour refers to the colours that may be formed in the molten glass by manipulating the furnace environment. Theophilus describes molten glass changing to a ‘saffron yellow colour’ which will eventually transform to a reddish yellow on further heating, he also refers to a ‘tawny colour, like flesh’ which, upon further heating will become ‘a light purple’ and later ‘a reddish purple, and exquisite’.Hawthorne et al (eds.) 1979, 55 These colour changes are the result of the behaviour, under redox conditions, of the iron and manganese oxides which are naturally present in beech wood ash. In the glass melt the iron and manganese behave as follows: Detail of the Jesse Tree panel from York Minster In an oxidising environment metal (and some non-metal) ions will lose electrons. In iron oxides, Fe2+ (ferrous) ions will become Fe3+ (ferric) ions.
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Eraclius’ De Coloribus et Artibus includes instructions for creating green and red glass by adding copper (probably in the form of ore or copper filings) to the batch, a method practiced since ancient times. (The chapters on how to make red, green and blue glass are missing from De Divers Artibus.) As with the iron/manganese colours, the colours formed by the addition of copper oxide to the glass are dependent on the different oxidation states of the added copper. In an oxidising environment blue cupric (Cu2+) ions are formed, in a strongly reducing environment red colloidal cuprous (Cu1+) oxide is formed and if reoxidised then green cuprous (Cu1+) oxide results. The production of bright reds and blues in particular was straightforward, as the addition of copper to the mix resulted in the reliable creation of red, blue and green.
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One of the main problems when generating hypotheses on the formation and evolution of objects in the Solar System is the lack of samples that can be analysed in the laboratory, where a large suite of tools are available and the full body of knowledge derived from terrestrial geology can be brought to bear. Direct samples from the Moon, asteroids and Mars are present on Earth, removed from their parent bodies and delivered as meteorites. Some of these have suffered contamination from the oxidising effect of Earth's atmosphere and the infiltration of the biosphere, but those meteorites collected in the last few decades from Antarctica are almost entirely pristine. The different types of meteorites that originate from the asteroid belt cover almost all parts of the structure of differentiated bodies: meteorites even exist that come from the core-mantle boundary (pallasites).
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The chimney was built to a height of around 19 metres; the high chimney increased the draught through the kiln and thus reduced the timing of the firing cycle to around 36 hours.Kerr, 39–40 Wares were placed inside stacked saggars on a floor of quartz sand; as the saggars protected their contents from direct flame both fuel and air could be introduced directly to the interior through vents, allowing temperature regulation throughout the kiln. Peepholes were used to observe the colour of flame, which changes according to the conditions and temperature. The hottest part of the kiln next to the firebox was used for crackle glazes; following inwards high-fired green and red glazes in a reducing atmosphere, then uncoloured, blue-glazed, and decorated ware at a moderate temperature, followed at the back by glazes to be fired at a lower temperature and turquoise-glazed ware in an oxidising atmosphere.
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It is not possible to remove a multi-pin part by melting solder on the pins sequentially, as one joint will solidify as the next is melted; pumps and solder wick are among methods to remove solder from all joints, leaving the part free to be removed. Suction pumps are also used with a suction head appropriate for each part to pick up and remove tiny surface mount devices once solder has melted, and to place parts. Hot air pumps blow air hot enough to melt all the solder around a small surface mounted part, and can be used for soldering parts in place, and for desoldering followed by removal before the solder solidifies by a vacuum pump or with tweezers. Hot air has a tendency to oxidise metals; a non-oxidising gas, usually nitrogen, can be used instead of air, at increased cost of equipment and consumables.
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199 Nihonium is expected to have a hexagonal close-packed crystalline structure, albeit based on extrapolation from those of the lighter group 13 elements: its density is expected to be around 16 g/cm3. A standard electrode potential of +0.6 V is predicted for the Nh+/Nh couple. The relativistic stabilisation of the 7s electrons is very high and hence nihonium should predominantly form the +1 oxidation state; nevertheless, as for copernicium, the +3 oxidation state should be reachable with highly electronegative ligands, with likely being of similar stability to (which is a strong oxidising agent, fuming in moist air and reacting with glass). Because of the shell closure at flerovium caused by spin-orbit coupling, nihonium is also one 7p electron short of a closed shell and would hence form a −1 oxidation state; in both the +1 and −1 oxidation states, nihonium should show more similarities to astatine than thallium.
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Unusual for proteins, this enzyme crystallizes when dialysed against distilled water. More so, the enzyme purifies as a consequence of crystallization, making cycles of crystallization an effective final purification step. Much like catalase, the reaction of cytochrome c peroxidase proceeds through a three-step process, forming first a Compound I and then a Compound II intermediate: : CCP + ROOH → Compound I + ROH + H2O : CCP-compound I + e− \+ H+ → Compound II : Compound II + e− \+ H+ → CCP CCP-catalyzed redox cycle CCP in the resting state has a ferric heme, and, after the addition of two oxidizing equivalents from a hydroperoxide (usually hydrogen peroxide), it becomes oxidised to a formal oxidation state of +5 (FeV, commonly referred to as ferryl heme. However, both low-temperature magnetic susceptibility measurements and Mössbauer spectroscopy show that the iron in Compound I of CCP is a +4 ferryl iron, with the second oxidising equivalent existing as a long-lived free-radical on the side-chain of the tryptophan residue (Trp-191).
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A flame is not necessary for this effect: in 1901, it was discovered that a hot Welsbach gas mantle (using ThO2 with 1% CeO2) remained at "full glow" when exposed to a cold unignited mixture of flammable gas and air. The light emitted by thorium dioxide is higher in wavelength than the blackbody emission expected from incandescence at the same temperature, an effect called candoluminescence. It occurs because ThO2 : Ce acts as a catalyst for the recombination of free radicals that appear in high concentration in a flame, whose deexcitation releases large amounts of energy. The addition of 1% cerium dioxide, as in gas mantles, heightens the effect by increasing emissivity in the visible region of the spectrum; and because cerium, unlike thorium, can occur in multiple oxidation states, its charge and hence visible emissivity will depend on the region on the flame it is found in (as such regions vary in their chemical composition and hence how oxidising or reducing they are).
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Neil Bartlett demonstrated that dioxygenyl hexafluoroplatinate (O2PtF6), containing the dioxygenyl cation, can be prepared at room temperature by direct reaction of oxygen gas (O2) with platinum hexafluoride (PtF6): :O2 \+ PtF6 → The compound can also be prepared from a mixture of fluorine and oxygen gases in the presence of a platinum sponge at 450 °C, and from oxygen difluoride () above 400 °C: :6 \+ 2 Pt → 2 \+ At lower temperatures (around 350 °C), platinum tetrafluoride is produced instead of dioxygenyl hexafluoroplatinate. Dioxygenyl hexafluoroplatinate played a pivotal role in the discovery of noble gas compounds. The observation that PtF6 is a powerful enough oxidising agent to oxidise O2 (which has a first ionization potential of 12.2 eV) led Bartlett to reason that it should also be able to oxidise xenon (first ionization potential 12.13 eV). His subsequent investigation yielded the first compound of a noble gas, xenon hexafluoroplatinate. is also found in similar compounds of the form O2MF6, where M is arsenic (As), antimony (Sb), gold (Au), niobium (Nb), ruthenium (Ru), rhenium (Re), rhodium (Rh), vanadium (V), or phosphorus (P).
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Nearly all elements in the periodic table form binary iodides. The exceptions are decidedly in the minority and stem in each case from one of three causes: extreme inertness and reluctance to participate in chemical reactions (the noble gases); extreme nuclear instability hampering chemical investigation before decay and transmutation (many of the heaviest elements beyond bismuth); and having an electronegativity higher than iodine's (oxygen, nitrogen, and the first three halogens), so that the resultant binary compounds are formally not iodides but rather oxides, nitrides, or halides of iodine. (Nonetheless, nitrogen triiodide is named as an iodide as it is analogous to the other nitrogen trihalides.) Given the large size of the iodide anion and iodine's weak oxidising power, high oxidation states are difficult to achieve in binary iodides, the maximum known being in the pentaiodides of niobium, tantalum, and protactinium. Iodides can be made by reaction of an element or its oxide, hydroxide, or carbonate with hydroiodic acid, and then dehydrated by mildly high temperatures combined with either low pressure or anhydrous hydrogen iodide gas.
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Greenwood and Earnshaw, p. 1240–2 Additionally, praseodymium forms a bronze diiodide; like the diiodides of lanthanum, cerium, and gadolinium, it is a praseodymium(III) electride compound. Praseodymium dissolves readily in dilute sulfuric acid to form solutions containing the chartreuse Pr3+ ions, which exist as [Pr(H2O)9]3+ complexes:Greenwood and Earnshaw, pp. 1242–4 :2 Pr (s) + 3 H2SO4 (aq) → 2 Pr3+ (aq) + 3 (aq) + 3 H2 (g) Dissolving praseodymium(IV) compounds in water does not result in solutions containing the yellow Pr4+ ions; because of the high positive standard reduction potential of the Pr4+/Pr3+ couple at +3.2 V, these ions are unstable in aqueous solution, oxidising water and being reduced to Pr3+. The value for the Pr3+/Pr couple is −2.35 V. However, in highly basic aqueous media, Pr4+ ions can be generated by oxidation with ozone. Although praseodymium(V) in the bulk state is unknown, the existence of praseodymium in its +5 oxidation state (with the stable electron configuration of the preceding noble gas xenon) under noble-gas matrix isolation conditions was reported in 2016. The species assigned to the +5 state were identified as [PrO2]+, its O2 and Ar adducts, and PrO2(η2-O2).
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Disposal of munitions with plastic explosives PE4 sticks, used alongside the L3A1 slab version by the British Armed Forces prior to the adoption of the later L20A1 block/L21A1 slab PE7 and L22A1 slab PE8 explosives The first plastic explosive was gelignite, invented by Alfred Nobel in 1875. Prior to World War I, the British explosives chemist Oswald Silberrad obtained British and U.S. patents for a series of plastic explosives called "Nitrols", composed of nitrated aromatics, collodion, and oxidising inorganic salts.US Patent # 1092758 The language of the patents indicate that at this time, Silberrad saw no need to explain to "those versed in the art" either what he meant by plasticity or why it may be advantageous, as he only explains why his plastic explosive is superior to others of that type. One of the simplest plastic explosives was Nobel's Explosive No. 808, also known as Nobel 808 (often just called Explosive 808 in the British Armed Forces during the Second World War), developed by the British company Nobel Chemicals Ltd well before World War II. It had the appearance of green plasticine with a distinctive smell of almonds.
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AgF2 is a strong fluorinating and oxidising agent. It is formed as an intermediate in the catalysis of gaseous reactions with fluorine by silver. With fluoride ions, it forms complex ions such as , the blue-violet , and . It is used in the fluorination and preparation of organic perfluorocompounds. This type of reaction can occur in three different ways (here Z refers to any element or group attached to carbon, X is a halogen): # CZ3H + 2 AgF2 → CZ3F + HF + 2 AgF # CZ3X + 2AgF2 → CZ3F + X2 \+ 2 AgF # Z2C=CZ2 \+ 2 AgF2 → Z2CFCFZ2 \+ 2 AgF Similar transformations can also be effected using other high valence metallic fluorides such as CoF3, MnF3, CeF4, and PbF4. is also used in the fluorination of aromatic compounds, although selective monofluorinations are more difficult: :C6H6 \+ 2 AgF2 → C6H5F + 2 AgF + HF oxidises xenon to xenon difluoride in anhydrous HF solutions. :2 AgF2 \+ Xe → 2 AgF + XeF2 It also oxidises carbon monoxide to carbonyl fluoride. :2 AgF2 \+ CO → 2 AgF + COF2 It reacts with water to form oxygen gas: :4 AgF2 \+ 4 H2O → 2 Ag2O + 8 HF + O2 can be used to selectively fluorinate pyridine at the ortho position under mild conditions.
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As such, iodide is the best leaving group among the halogens, to such an extent that many organoiodine compounds turn yellow when stored over time due to decomposition into elemental iodine; as such, they are commonly used in organic synthesis, because of the easy formation and cleavage of the C–I bond. They are also significantly denser than the other organohalogen compounds thanks to the high atomic weight of iodine. A few organic oxidising agents like the iodanes contain iodine in a higher oxidation state than −1, such as 2-iodoxybenzoic acid, a common reagent for the oxidation of alcohols to aldehydes, and iodobenzene dichloride (PhICl2), used for the selective chlorination of alkenes and alkynes. One of the more well-known uses of organoiodine compounds is the so-called iodoform test, where iodoform (CHI3) is produced by the exhaustive iodination of a methyl ketone (or another compound capable of being oxidised to a methyl ketone), as follows: :450px Some drawbacks of using organoiodine compounds as compared to organochlorine or organobromine compounds is the greater expense and toxicity of the iodine derivatives, since iodine is expensive and organoiodine compounds are stronger alkylating agents.
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Though the recipe of tin glazes may differ in different sites and periods, the process of the production of tin glazes is similar. Generally speaking, the first step of the production of tin glazes is to mix tin and lead in order to form oxides, which was then added to a glaze matrix (alkali-silicate glaze, for example) and heated.Canby, S. R. 1997 After the mixture cooled, the tin oxide crystallises as what has been mentioned above, therefore generates the so-called white tin-opacified glazes. Besides, the body of tin-opacified wares is generally calcareous clays containing 15-25% CaO, of which the thermal expansion coefficient is close to that of tin glazes, thus avoid crazing during the firing process.Tite, M. S. 1991Ravaglioli, A., A. Keajewski, M. S. Tite, R. R. Burn, P. A. Simpson, and G. C. Bojani. 1996 On the other hand, the calcareous clay fired in an oxidising atmosphere results in a buff colour, thus lower the concentration of tin oxide used Tite, M. S., Freestone, I. and Manson, R.B., "Lead glazes in antiquity - methods of production and reasons for use", archaeometry, 1998, 40:241-260 The white opaque surface makes tin glaze a good base for painted decoration.
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