The solvated electron reacts with oxygen to form a superoxide radical (O2.−). With nitrous oxide, solvated electrons react to form hydroxyl radicals (HO.). The solvated electrons can be scavenged from both aqueous and organic systems with nitrobenzene or sulfur hexafluoride. A common use of sodium dissolved in liquid ammonia is the Birch reduction.
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Other reactions where sodium is used as a reducing agent also are assumed to involve solvated electrons, e.g. the use of sodium in ethanol as in the Bouveault–Blanc reduction. Solvated electrons are involved in the reaction of sodium metal with water. Two solvated electrons combine to form molecular hydrogen and hydroxide ion.
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Solvated electrons are powerful reducing agents and are often used in chemical synthesis.
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This orientation has great influence on the permittivity of the solvent that varies with field strength. The IHP passes through the centers of these molecules. Specifically adsorbed, partially solvated ions appear in this layer. The solvated ions of the electrolyte are outside the IHP.
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The diffusivity of the solvated electron in liquid ammonia can be determined using potential-step chronoamperometry.
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A solvated ligand that binds the protein of interest is likely to exist as an equilibrium mixture of several conformers. Likewise the solvated protein also exists as several conformers in equilibrium. Formation of protein-ligand complex includes displacement of the solvent molecules that occupy the binding site of the ligand, to produce a solvated complex. Because this necessarily means that the interaction is entropically disfavored, highly favorable enthalpic contacts between the protein and the ligand must compensate for the entropic loss.
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Solvated Metal Atom Dispersion is a method of producing highly reactive solvated nanoparticles. Samples of the metal (or ceramic) are heated to produce free atoms (or species), as in PVD evaporation. These are then co- depositied with a suitable organic frozen solvent (e.g. toluene) at very low temperatures (on the order of 70K).
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The simplest anion which can be a conjugate base is the solvated electron whose conjugate acid is the atomic hydrogen.
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The Brønsted–Lowry definition applies to other solvents, such as dimethyl sulfoxide: the solvent S acts as a base, accepting a proton and forming the conjugate acid SH+. :HA + S A− \+ SH+. In solution chemistry, it is common to use H+ as an abbreviation for the solvated hydrogen ion, regardless of the solvent. In aqueous solution H+ denotes a solvated hydronium ion rather than a proton.
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In solution chemistry, it is usual to use H+ as an abbreviation for the solvated hydrogen ion, regardless of the solvent. In aqueous solution H+ denotes a solvated hydronium ion.The bare proton does not exist in aqueous solution. It is a very strong acid and combines the base, water, to form the hydronium ion :H+ \+ H2O → H3O+ The hydronium ion forms various weak complexes by hydrogen bonding with more water molecules.
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Methane clathrates, crystalline solids formed by methane being solvated and trapped in a cage of water molecules, burn robustly. Methane () is the simplest hydrocarbon compound. Although it is relatively hydrophobic, its small size allows it to be solvated in a crystalline shell of water at low temperatures and high pressures. This forms a solid crystalline compound similar to ice that can be found in great quantities under the sediments of the planet’s ocean floors.
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Tl2SO4 adopts the same structure as K2SO4. In aqueous solution, the thallium(I) cations and the sulfate anions are separated and highly solvated. Thallium(I) sulfate crystals have a C2 symmetry.
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Charles A. Kraus measured the electrical conductance of metal ammonia solutions and in 1907 attributed it to the electrons liberated from the metal. In 1918, G. E. Gibson and W. L. Argo introduced the solvated electron concept. They noted based on absorption spectra that different metals and different solvents (methylamine, ethylamine) produce the same blue color, attributed to a common species, the solvated electron. In the 1970s, solid salts containing electrons as the anion were characterized.
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The outer Helmholtz plane (OHP) passes through the centres of solvated ions at the distance of their closest approach to the electrode. Finally the diffuse layer is the region beyond the OHP.
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The relative magnitude of the signals quantitatively reveals the enantiomeric purity of the analyte. Also, a model of the solvated complex may be used to deduce absolute configuration of an enantioenriched analyte.
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By an IUPAC definition, solvation is an interaction of a solute with the solvent, which leads to stabilization of the solute species in the solution. In the solvated state, an ion in a solution is surrounded or complexed by solvent molecules. Solvated species can often be described by coordination number, and the complex stability constants. The concept of the solvation interaction can also be applied to an insoluble material, for example, solvation of functional groups on a surface of ion-exchange resin.
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The original synthesis of VI2 involved reaction of the elements. Solvated vanadium(II) iodides can be prepared by reduction of vanadium(III) chlorides with trimethylsilyl iodide. It reacts with anhydrous ammonia to give the hexaammine complex.
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An oxygen-sensitive colourless solid, it is a reagent in organometallic and organic chemical research. The dioxane solvated sodium salt is known as Collman's reagent, in recognition of James P. Collman an early popularizer of its use.
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Pseudocapacitance may originate from the electrode structure, especially from the material pore size. The use of carbide-derived carbons (CDCs) or carbon nanotubes (CNTs) as electrodes provides a network of small pores formed by nanotube entanglement. These nanoporous materials have diameters in the range of <2 nm that can be referred to as intercalated pores. Solvated ions in the electrolyte are unable to enter these small pores, but de-solvated ions that have reduced their ion dimensions are able to enter, resulting in larger ionic packing density and increased charge storage.
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To perform such a calculation, one needs theoretical methods that can calculate the effect of the protein interior on a pKa value, and knowledge of the pKa values of amino acid side chains in their fully solvated states.
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Solutions of pure buckminsterfullerene have a deep purple color. Solutions of are a reddish brown. The higher fullerenes to have a variety of colors. Millimeter-sized crystals of and , both pure and solvated, can be grown from benzene solution.
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This is then warmed towards room temperature, producing solvated metal atoms or (over time) larger clusters. Sometimes, catalysts supports (such as SiO2 or Al2O3) are added to improve nucleation, as it can more readily take place on surface OH groups.
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Hydrogen ion clusters can be formed in liquid helium or with lesser cluster size in pure hydrogen. is far more common than higher even numbered clusters. is stable in solid hydrogen. The positive charge is balanced by a solvated electron.
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No compounds containing the Zn ion have been characterized. Whilst zinc chloride is very soluble in water, solutions cannot be considered to contain simply solvated Zn2+ ions and Cl− ions, ZnClxH2O(4−x) species are also present. Aqueous solutions of ZnCl2 are acidic: a 6 M aqueous solution has a pH of 1. The acidity of aqueous ZnCl2 solutions relative to solutions of other Zn2+ salts is due to the formation of the tetrahedral chloro aqua complexes where the reduction in coordination number from 6 to 4 further reduces the strength of the O–H bonds in the solvated water molecules.
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In aqueous solution and in other donor solvents, metal cations are surrounded by between 4 and 9 solvent molecules in the primary solvation shell,Burgess, Chapter 5, "Solvation numbers" An alternative name for a solvent-shared ion pair is an outer-sphere complex. This usage is common in co-ordination chemistry and denotes a complex between a solvated metal cation and an anion. Similarly, a contact ion pair may be termed an inner-sphere complex. The essential difference between the three types is the closeness with which the ions approach each other: fully solvated > solvent-shared > contact.
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This w/w emulsion was generated when the different water-solvated molecular functional groups get segregated in an aqueous mixture consisting of polymer and liquid crystal molecules. Structure of disodium cromolyn glycate, DSCG This water-in-water emulsion consists of liquid crystals suspended as water- solvated droplets dispersed in a solution of polymer whose solvent is also water. The liquid crystal component of the emulsion is disodium cromolyn glycate (DSCG). This molecule is an anti-asthmatic drug, but also exists as a special type of liquid crystal when the concentration of DSCG is ~9-21 wt%.
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A monomeric form crystallizes with chloroform in the lattice. It features planar Co centers. Salcomine is both a Lewis acid and a reductant. Several solvated derivatives bind O2 to give derivatives of the type (μ-O2)[Co(salen)py]2 and [Co(salen)py(O2)].
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During potential variant experiments common to go through a redox couple in which the major species is transformed from a species that is soluble in the solution to one that is insoluble. This results in nucleation process in which a new species plates out on the working electrode. If a species has been deposited on the electrode during a potential sweep then on the return sweep a stripping wave is usually observed. :[MLn]+(solvated) \+ e− → [MLn]0(solid) nucleation :[MLn]0(solid) → e− \+ [MLn]+(solvated) stripping While the nucleation wave may be pronounced or difficult the detect the stripping wave is usually very distinct.
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The alkali metals dissolve slowly in liquid ammonia, forming ammoniacal solutions of solvated metal cation M+ and solvated electron e−, which react to form hydrogen gas and the alkali metal amide (MNH2, where M represents an alkali metal): this was first noted by Humphry Davy in 1809 and rediscovered by W. Weyl in 1864. The process may be speeded up by a catalyst. Similar solutions are formed by the heavy divalent alkaline earth metals calcium, strontium, barium, as well as the divalent lanthanides, europium and ytterbium. The amide salt is quite insoluble and readily precipitates out of solution, leaving intensely coloured ammonia solutions of the alkali metals.
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In the eastern area, the amber is found in a sediment formation of organic-rich laminated sand, sandy clay, intercalated lignite, and as well as some solvated beds of gravel and calcarenite.Schlee, D. (1984): Besonderheiten des Dominikanischen Bernsteins. – Stuttgarter Beitr. Naturk., C, 18: 63-71; Stuttgart.
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Uncharged compounds such as methane can also be solvated by water and also have a hydration number. Although solvation shells can contain inner and outer shell solvent-solute interactions, the hydration number generally focuses on the inner shell solvent molecules that most directly interact with the solute.
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This result developed in 2015 was completely new to chemistry. His research, supported by the YouTube community, has been published in the journal Nature Chemistry. On 5 June 2020, his research on solvated electrons dissolved in ammonia was published on the front page of the science journal Science.
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Few inorganic fluorides are soluble in water without undergoing significant hydrolysis. In terms of its reactivity, fluoride differs significantly from chloride and other halides, and is more strongly solvated in protic solvents due to its smaller radius/charge ratio. Its closest chemical relative is hydroxide, since both have similar geometries.
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The SEI layer normally forms an ion conductive layer that is solvated by the electrolyte, which prevents further growth. However, due to the swelling of the silicon, the SEI layer cracks and become porous. Thus, it can thicken. A thick SEI layer results in a higher cell resistance, which decreases cell efficiency.
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The sizes are arbitrary and not necessarily similar as illustrated. The cation is coloured red and the anion is coloured blue. The green area represents solvent molecules in a primary solvation shell; secondary solvation is ignored. When both ions have a complete primary solvation sphere, the ion pair may be termed fully solvated.
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In 1907, Charles Krause identified the colour as being due to the presence of solvated electrons, which contribute to the high electrical conductivity of these solutions. At low concentrations (below 3 M), the solution is dark blue and has ten times the conductivity of aqueous sodium chloride; at higher concentrations (above 3 M), the solution is copper-coloured and has approximately the conductivity of liquid metals like mercury. In addition to the alkali metal amide salt and solvated electrons, such ammonia solutions also contain the alkali metal cation (M+), the neutral alkali metal atom (M), diatomic alkali metal molecules (M2) and alkali metal anions (M−). These are unstable and eventually become the more thermodynamically stable alkali metal amide and hydrogen gas.
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Solvated ions (cations) 5. Specifically adsorbed ions (redox ion, which contributes to the pseudocapacitance), 6. Molecules of the electrolyte solvent D. C. Grahame modified the Stern model in 1947. He proposed that some ionic or uncharged species can penetrate the Stern layer, although the closest approach to the electrode is normally occupied by solvent molecules.
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Surfactant enhanced etching is used to modify ion track shapes. It is based on self-organized monolayers. The monolayers are semi-permeable for the solvated ions of the etch medium and reduce surface attack. Depending on the relative concentration of the surfactant and the etch medium, barrel or cylindrical shaped ion track pores are obtained.
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Carbohydrates are typically stored as long polymers of glucose molecules with glycosidic bonds for structural support (e.g. chitin, cellulose) or for energy storage (e.g. glycogen, starch). However, the strong affinity of most carbohydrates for water makes storage of large quantities of carbohydrates inefficient due to the large molecular weight of the solvated water-carbohydrate complex.
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Unfortunately, molecules that are polar enough to support these solvated ion pairs often interrupt the polymerization in other ways, such as by destroying propagating species or coordinating with initiator ions, and so they are seldom utilized. Typical solvents for ionic polymerization include non-polar molecules such as pentane, or moderately polar molecules such as chloroform.
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The hydroxide ion forms salts, some of which dissociate in aqueous solution, liberating solvated hydroxide ions. Sodium hydroxide is a multi-million-ton per annum commodity chemical. A hydroxide attached to a strongly electropositive center may itself ionize, liberating a hydrogen cation (H+), making the parent compound an acid. The corresponding electrically neutral compound HO• is the hydroxyl radical.
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Redox reactions are preferably run in polar solvents. Donor and acceptor then have a solvent shell and the precursor and successor complexes are solvated also. The closest molecules of the solvent shell, or the ligands in complexes, are tightly bound and constitute the "inner sphere". Reactions in which these participate are called inner sphere redox reactions.
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MBN Explorer is complemented with MBN Studio \- a multi-task program for molecular modeling and design, as well as for visualization and analysis of results of the simulations performed with MBN Explorer. The built-in molecular modeler can be used to construct isolated and solvated biomolecules, condensed molecular materials, carbon nanotubes and graphene sheets, nanoparticles and crystalline samples.
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In computational chemistry, a solvent model is a computational method that accounts for the behavior of solvated condensed phases. Solvent models enable simulations and thermodynamic calculations applicable to reactions and processes which take place in solution. These include biological, chemical and environmental processes. Such calculations can lead to new predictions about the physical processes occurring by improved understanding.
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However, even in this case, such solvated hydrogen cations are more realistically conceived as being organized into clusters that form species closer to H. Other oxonium ions are found when water is in acidic solution with other solvents. Although exotic on Earth, one of the most common ions in the universe is the ion, known as protonated molecular hydrogen or the trihydrogen cation.
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A particular notable contribution of Prof. Rode's research is the development and application of hybrid quantum mechanical/molecular mechanical simulation techniques, focusing on a broad range of problems in solution chemistry. In 2004 an improved technique known as quantum mechanical charge field molecular dynamics explicitly aimed at the treatment of solvated systems has been developed in Prof. Rode's research group.
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Pseudocapacitance is accompanied by an electron charge-transfer between electrolyte and electrode coming from a de-solvated and adsorbed ion. One electron per charge unit is involved. The adsorbed ion has no chemical reaction with the atoms of the electrode (no chemical bonds arise) since only a charge-transfer takes place. Faradaic pseudocapacitance only occurs together with static double-layer capacitance.
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The diameter of the selectivity filter is ideal for the potassium cation, but too big for the smaller sodium cation. Hence the potassium cations are well "solvated" by the protein carbonyl groups, but these same carbonyl groups are too far apart to adequately solvate the sodium cation. Hence, the passage of potassium cations through this selectivity filter is strongly favored over sodium cations.
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Around the sites of these collisions chemical bonds are broken, creating short lived radicals (e.g. the hydroxyl radical, the hydrogen atom and solvated electrons). These radicals cause further chemical changes by bonding with and or stripping particles from nearby molecules. When collisions occur in cells, cell division is often suppressed, halting or slowing the processes that cause the food to mature.
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Other methods have been published including reacting the finely powdered metal with mercuric chloride at high temperature in a sealed tube. A variety of routes to solvated YbCl3 have been reported including reaction of the metal with various halocarbons in the present of a donor solvent such as THF, or dehydration of the hydrated chloride using trimethylsilyl or thionyl chloride, again in a solvent such as THF.
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Example of a hybrid quantum mechanical/molecular mechanical simulation of aqueous Sn(II) performed by Rode et al.Hofer, Thomas; Pribil, Andreas; Randolf, Bernhard; Rode, Bernd M. (2005); "Structure and dynamics of solvated Sn(II) in aqueous solution - an ab initio QM/MM MD approach", J. Am. Chem. Soc. 2005, 127(41), pp. 14231–14238. DOI:10.1021/ja052700f Oxygen atoms of first shell molecules are shown in red.
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The reaction to produce fluoroantimonic acid results in formation of the fluoronium ion as a major species in equilibrium: :SbF5 \+ 2 HF ⇄ + H2F+ However, the speciation of "fluoroantimonic acid" is complex, and consists of a mixture of HF-solvated protons, [ (e.g., H3F2+), and SbF5-adducts of fluoride (e.g., Sb4F21–). Thus, the formula "[H2F]+SbF6–" is a convenient but oversimplified approximation of the true composition.
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Simplified view of a double-layer of negative ions in the electrode and solvated positive ions in the liquid electrolyte, separated by a layer of polarized solvent molecules. Helmholtz laid the theoretical foundations for understanding the double layer phenomenon. The formation of double layers is exploited in every electrochemical capacitor to store electrical energy. Every capacitor has two electrodes, mechanically separated by a separator.
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For instance, carbonate has a great effect upon the diagram for uranium. (See diagrams at right). The presence of trace amounts of certain species such as chloride ions can also greatly affect the stability of certain species by destroying passivating layers. In addition, changes in temperature and concentration of solvated ions in solution will shift the equilibrium lines in accordance with the Nernst equation.
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They enter the negative electrode and flow through the external circuit to the positive electrode where a second double-layer with an equal number of anions has formed. The electrons reaching the positive electrode are not transferred to the anions forming the double-layer, instead they remain in the strongly ionized and "electron hungry" transition-metal ions of the electrode's surface. As such, the storage capacity of faradaic pseudocapacitance is limited by the finite quantity of reagent in the available surface. A faradaic pseudocapacitance only occurs together with a static double-layer capacitance, and its magnitude may exceed the value of double-layer capacitance for the same surface area by factor 100, depending on the nature and the structure of the electrode, because all the pseudocapacitance reactions take place only with de-solvated ions, which are much smaller than solvated ion with their solvating shell.
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In aqueous solution both hydrogen and hydroxide ions are strongly solvated, with hydrogen bonds between oxygen and hydrogen atoms. Indeed, the bihydroxide ion has been characterized in the solid state. This compound is centrosymmetric and has a very short hydrogen bond (114.5 pm) that is similar to the length in the bifluoride ion (114 pm). In aqueous solution the hydroxide ion forms strong hydrogen bonds with water molecules.
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At lower concentrations the equilibrium is on the side of the monomeric species. Both, dimer and monomer are co- coordinated by LiCl. At temperatures below -50°C LiCl gets separated from the magnesium amide in sense of a stable [LiCl]2 dimer solvated by four THF molecules. iPr-Turbo-Hauser Base in THF solution The solid state structure of TMPMgCl·LiCl remains almost completely in THF solution independently of temperature and concentration.
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A classic example of this process is the quinine sulfate fluorescence, which can be quenched by the use of various halide salts. The excited molecule can de-excite by increasing the thermal energy of the surrounding solvated ions. Several natural molecules perform a fast internal conversion. This ability to transform the excitation energy of photon into heat can be a crucial property for photoprotection by molecules such as melanin.
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Another advantage of potassium-ion battery over lithium-ion battery is the possibility for charging faster. The prototype employed a electrolyte though almost all common electrolyte salts can be used. In addition, ionic liquids have also recently been reported as stable electrolytes with a wide electrochemical window. The chemical diffusion coefficient of in the cell is higher than that of in lithium batteries, due to a smaller Stokes radius of solvated .
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Solvated electrolyte ions (cations) 5. Specifically adsorbed ions (redox ion, which contributes to the pseudocapacitance), 6. Molecules of the solvent A fundamental difference between redox reactions in batteries and in electrochemical capacitors (supercapacitors) is that in the latter, the reactions are a very fast sequence of reversible processes with electron transfer without any phase changes of the electrode molecules. They do not involve making or breaking chemical bonds.
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The de-solvated atoms or ions contributing the pseudocapacitance simply cling to the atomic structure of the electrode and charges are distributed on surfaces by physical adsorption processes. Compared with batteries, supercapacitor faradaic processes are much faster and more stable over time, because they leave only traces of reaction products. Despite the reduced amount of these products, they cause capacitance degradation. This behavior is the essence of pseudocapacitance.
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One layer is within the solid electrode (at the surfaces of crystal grains from which it is made that are in contact with the electrolyte). The other layer, with opposite polarity, forms from dissolved and solvated ions distributed in the electrolyte that have moved towards the polarized electrode. These two layers of polarized ions are separated by a monolayer of solvent molecules. The molecular monolayer forms the inner Helmholtz plane (IHP).
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Hydrochloric acid is the salt of the hydronium ion, H3O+ and chloride. It is usually prepared by treating HCl with water. : HCl + H2O -> H3O^+ + Cl^- However, the speciation of hydrochloric acid is more complicated than this simple equation implies. The structure of bulk water is infamously complex, and likewise, the formula H3O+ is also a gross oversimplification of the true nature of the solvated proton, H+(aq), present in hydrochloric acid.
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In chemistry the intimate ion pair concept introduced by Saul Winstein describes the interactions between a cation, anion and surrounding solvent molecules. In ordinary aqueous solutions of inorganic salts an ion is completely solvated and shielded from the counterion. In less polar solvents two ions can still be connected to some extent. In a tight or intimate or contact ion pair there are no solvent molecules between the two ions.
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Several important inorganic acids contain fluorine. They are generally very strong because of the high electronegativity of fluorine. One such acid, fluoroantimonic acid (HSbF6), is the strongest charge-neutral acid known. The dispersion of the charge on the anion affects the acidity of the solvated proton (in form of ): The compound has an extremely low pKa of −28 and is 10 quadrillion (1016) times stronger than pure sulfuric acid.
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Hexafluorosilicic acid is generally assumed to consist of oxonium ions charge balanced by hexafluorosilicate dianions as well as water. In aqueous solution, the hydronium cation (H3O+) is traditionally equated with a solvated proton, and as such, the formula for this compound is often written as . Extending that metaphor, the isolated compound is then written as , or .The situation is similar to that for chloroplatinic acid, fluoroboric acid, and hexafluorophosphoric acid.
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With fully solvated and solvent-shared ion pairs the interaction is primarily electrostatic, but in a contact ion pair some covalent character in the bond between cation and anion is also present. An ion triplet may be formed from one cation and two anions or from one anion and two cations. Higher aggregates, such as a tetramer (AB)4, may be formed. Ternary ion associates involve the association of three species.
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Brønsted acids. The hydrogen ion H+ never exists on its own in a condensed phase, as it is always solvated to a certain extent. The high negative value of H0 in SbF5/HSO3F mixtures indicates that the solvation of the hydrogen ion is much weaker in this solvent system than in water. Other way of expressing the same phenomenon is to say that SbF5·FSO3H is a much stronger proton donor than H3O+.
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When ionic compounds dissolve, the individual ions dissociate and are solvated by the solvent and dispersed throughout the resulting solution. Because the ions are released into solution when dissolved, and can conduct charge, soluble ionic compounds are the most common class of strong electrolytes, and their solutions have a high electrical conductivity. The aqueous solubility of a variety of ionic compounds as a function of temperature. Some compounds exhibiting unusual solubility behaviour have been included.
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A sodium ion solvated by water molecules. Solvation describes the interaction of solvent with dissolved molecules. Both ionized and uncharged molecules interact strongly with solvent, and the strength and nature of this interaction influence many properties of the solute, including solubility, reactivity, and color, as well as influencing the properties of the solvent such as the viscosity and density. In the process of solvation, ions are surrounded by a concentric shell of solvent.
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Protophilic solvents are basic in character and react with acids to form solvated protons. : + ⇌ + A weakly basic solvent has less tendency than a strongly basic one to accept a proton. Similarly a weak acid has less tendency to donate protons than a strong acid. As a result, a strong acid such as perchloric acid exhibits more strongly acidic properties than a weak acid such as acetic acid when dissolved in a weakly basic solvent.
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In liquid water there is some self-dissociation giving hydronium ions and hydroxide ions. :2 + The equilibrium constant for this reaction, known as the ionic product of water,Kw, has a value of about at 25 °C. At neutral pH, the concentration of the hydroxide ion () equal to that of the (solvated) hydrogen ion (), with a value close to 10−7 mol L−1 at 25 °C. See data page for values at other temperatures.
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Hydronium is the cation that forms from water in the presence of hydrogen ions. These hydrons do not exist in a free state - they are extremely reactive and are solvated by water. An acidic solute is generally the source of the hydrons, but hydronium ions exist even in pure water. This special case of water reacting with water to produce hydronium (and hydroxide) ions is commonly known as the self-ionization of water.
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Fluoroboric acid or tetrafluoroboric acid (archaically, fluoboric acid) is an inorganic compound with the chemical formula [H+][BF4−], where H+ represents the solvated proton. The solvent can be any suitably Lewis basic entity. For instance, in water, it can be represented by (oxonium tetrafluoroborate), although more realistically, several water molecules solvate the proton: [H(H2O)n+][BF4−]. The ethyl ether solvate is also commercially available: [H(Et2O)n+][BF4−], where n is most likely 2.
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The tailored sizes of pores in nano-structured carbon electrodes can maximize ion confinement, increasing specific capacitance by faradaic adsorption treatment. Occupation of these pores by de- solvated ions from the electrolyte solution occurs according to (faradaic) intercalation.A.G. Pandolfo, A.F. Hollenkamp, Carbon properties and their role in supercapacitors , Journal of Power Sources 157 (2006) 11–27B.P. Bakhmatyuk, B.Ya. Venhryn, I.I. Grygorchak, M.M. Micov and S.I. Mudry, INTERCALATION PSEUDO-CAPACITANCE IN CARBON SYSTEMS OF ENERGY STORAGEP.
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Therefore, the following routes are possible options: (i) For M=Ln including La, Ce, Pr, Nd and Gd, unsolvated cation route is preferred since [(C5Me5)2LnH]x complexes are too reactive. 602x602px Notably, the synthesis of (C5Me5)3La and (C5Me5)3Ce requires the usage of silylated glassware since they are easily oxidized. (ii) For M=actinide like U, solvated cation route can be used. 604x604px IV. Synthesis of (C5Me5)3MZ with Z=X, H, etc.
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Ammonium sulfate precipitation is a common method for protein purification by precipitation. As the ionic strength of a solution increases, the solubility of proteins in that solution decreases. Ammonium sulfate is extremely soluble in water due to its ionic nature, therefore it can "salt out" proteins by precipitation. Due to the high dielectric constant of water, the dissociated salt ions being cationic ammonium and anionic sulfate are readily solvated within hydration shells of water molecules.
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Cavities and channels in an electride An electride is an ionic compound in which an electron is the anion. Solutions of alkali metals in ammonia are electride salts.Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. In the case of sodium, these blue solutions consist of [Na(NH3)6]+ and solvated electrons: :Na + 6 NH3 → [Na(NH3)6]+,e− The cation [Na(NH3)6]+ is an octahedral coordination complex.
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This w/w emulsion also represents a new class of polymer dispersed liquid crystals(PDLC). Traditionally known PDLC consists of oil-in-water emulsion where the oily droplet is a thermotropic liquid crystal such as 4-pentyl-4'-cyanobiphenyl (5CB), and the water phase contains certain polymers. In comparison, this water-in-water emulsion consists of Polymer- Dispersed Lyotropic Liquid Crystals, where the lyotropic liquid crystal is DSCG molecules solvated in water.
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Pseudocapacitance is accompanied by an electron charge-transfer between electrolyte and electrode coming from a de- solvated and adsorbed ion. One electron per charge unit is involved. The adsorbed ion has no chemical reaction with the atoms of the electrode (no chemical bonds arise) since only a charge-transfer takes place. An example is a redox reaction where the ion is O2+ and during charging, one electrode hosts a reduction reaction and the other an oxidation reaction.
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Liquid ammonia will dissolve all of the alkali metals and other electropositive metals such as Ca, Sr, Ba, Eu, and Yb (also Mg using an electrolytic process). At low concentrations (<0.06 mol/L), deep blue solutions are formed: these contain metal cations and solvated electrons, free electrons that are surrounded by a cage of ammonia molecules. These solutions are very useful as strong reducing agents. At higher concentrations, the solutions are metallic in appearance and in electrical conductivity.
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Relative to the more commonly encountered methylmagnesium bromide and methylmagnesium iodide, methylmagnesium chloride offers the advantages of low equivalent weight and low cost. It is prepared by the reaction of methyl chloride and magnesium in ethyl ether. Structure of CH3MgCl(thf)2, which is representative of the species in donor solvents. As with most Grignard reagents, methylmagnesium chloride is highly solvated by ether solvents via coordination from two oxygen atoms to give a tetrahedrally bonded magnesium center.
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In the absence of donor ligand, lithium cation is closely coordinated to the oxygen atom, however, when the lithium cation is solvated by HMPA, the coordination between carbonyl oxygen and lithium ion is weakened. This method generally cannot be used to affect the regioselectivity of alkyl- and aryllithium reagents. :1,4vs1,2 addition Organolithium reagents can also perform enantioselective nucleophilic addition to carbonyl and its derivatives, often in the presence of chiral ligands. This reactivity is widely applied in the industrial syntheses of pharmaceutical compounds.
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Metal cations in the aqueous feed raffinate are generally solvated by coordinating water molecules through the donor oxygen atoms to form aquo ions [M(H2O)_{n}]^{3+} (n = 4-9) . The complexation of a metal ion implies therefore the replacement of the coordinated water molecules with the respective ligands. The speed of this substitution plays a crucial role in the complexation kinetics and the following extraction processes. The replacement can be slow for an inert complex or rapid for a labile complex.
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In electrolytes, electrical conduction happens not by band electrons or holes, but by full atomic species (ions) traveling, each carrying an electrical charge. The resistivity of ionic solutions (electrolytes) varies tremendously with concentration – while distilled water is almost an insulator, salt water is a reasonable electrical conductor. Conduction in ionic liquids is also controlled by the movement of ions, but here we are talking about molten salts rather than solvated ions. In biological membranes, currents are carried by ionic salts.
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Stable polymerizing cations are only possible using monomers with electron-releasing groups, and stable anions with monomers with electron-withdrawing groups as substituents. While radical polymerization rate is governed nearly exclusively by monomer chemistry and radical stability, successful ionic polymerization is as strongly related to reaction conditions. Poor monomer purity quickly leads to early termination, and solvent polarity has a great effect on reaction rate. Loosely-coordinated and solvated ion pairs promote more reactive, fast- polymerizing chains, unencumbered by their counterions.
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CrCl3 is a Lewis acid, classified as "hard" according to the Hard-Soft Acid-Base theory. It forms a variety of adducts of the type [CrCl3L3]z, where L is a Lewis base. For example, it reacts with pyridine () to form an adduct: :CrCl3 \+ 3 C5H5N → CrCl3(C5H5N)3 Treatment with trimethylsilylchloride in THF gives the anhydrous THF complex:Philip Boudjouk, Jeung-Ho So "Solvated and Unsolvated Anhydrous Metal Chlorides from Metal Chloride Hydrates" Inorganic Syntheses, 2007, vol. 29, p. 108-111. :CrCl3.
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A quantitative measure for solvation power of solvents is given by donor numbers. Although early thinking was that a higher ratio of a cation's ion charge to ionic radius, or the charge density, resulted in more solvation, this does not stand up to scrutiny for ions like iron(III) or lanthanides and actinides, which are readily hydrolyzed to form insoluble (hydrous) oxides. As these are solids, it is apparent that they are not solvated. Strong solvent-solute interactions make the process of solvation more favorable.
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These bases do not contain a hydroxide ion but nevertheless react with water, resulting in an increase in the concentration of hydroxide ion. Also, some non-aqueous solvents contain Brønsted bases which react with solvated protons. For example in liquid ammonia, NH2- is the basic ion species which accepts protons from NH4+, the acidic species in this solvent. G. N. Lewis realized that water, ammonia and other bases can form a bond with a proton due to the unshared pair of electrons that the bases possess.
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Brønsted and Lowry characterized an acid–base equilibrium as involving a proton exchange reaction: Includes discussion of many organic Brønsted acids. Chapter 5: Acids and Bases Chapter 6: Acids, Bases and Ions in Aqueous Solution :acid + base conjugate base + conjugate acid. An acid is a proton donor; the proton is transferred to the base, a proton acceptor, creating a conjugate acid. For aqueous solutions of an acid HA, the base is water; the conjugate base is A− and the conjugate acid is the solvated hydrogen ion.
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His research in Leiden and later in Eindhoven was focused on organic chemistry as the homogeneous catalysis of the oxidation of hydrocarbons with stable carbenium ions as the pentamethylbenzyl cation Van Pelt, P. et al. (1976) "Proton acid catalyzed hydride transfer from alkanes to methylated benzyl cations. Part III: Solvated alkanes as Hydrogen-donating intermediates", Journal of the American Chemical Society,Vol. 98, pp. 5864-5870 and the chiral induction with the redox couple NADH-NAD+ in the nearly 100% stereospecific hydride transfer to ketones and imines.
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As water solvated droplets in a w/w emulsion, DSCG molecules would align in a preferred direction on the surface of the droplet. To minimize the overall energy of the system, the DSCG molecules in the droplet prefer to align either parallel or perpendicular to the surfaces of the droplets.(Fig. 4A,B). right The stability of this water-in-water emulsion from coalescence is attributed to three molecular forces: 1\. The separation of different molecular forces at the beginning of the droplet formation.
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New York: McGraw-Hill. . p. 234. does not imply a hydrogen ion concentration of 1021 mol/dm3: such a "solution" would have a density more than a hundred times greater than a neutron star. Rather, H0 = −21 implies that the reactivity (protonating power) of the solvated hydrogen ions is 1021 times greater than the reactivity of the hydrated hydrogen ions in an aqueous solution of pH 0\. The actual reactive species are different in the two cases, but both can be considered to be sources of H+, i.e.
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Simplified view of a double-layer of negative ions in the electrode and solvated positive ions in the liquid electrolyte, separated by a layer of polarized solvent molecules. Every electrochemical capacitor has two electrodes, mechanically separated by a separator, which are ionically connected to each other via the electrolyte. The electrolyte is a mixture of positive and negative ions dissolved in a solvent such as water. At each of the two electrode surfaces originates an area in which the liquid electrolyte contacts the conductive metallic surface of the electrode.
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This interface forms a common boundary among two different phases of matter, such as an insoluble solid electrode surface and an adjacent liquid electrolyte. In this interface occurs a very special phenomenon of the double layer effect. Applying a voltage to an electrochemical capacitor causes both electrodes in the capacitor to generate electrical double-layers. These double-layers consist of two layers of charges: one electronic layer is in the surface lattice structure of the electrode, and the other, with opposite polarity, emerges from dissolved and solvated ions in the electrolyte.
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This new way of looking at the laser interaction with matter was first proposed by Tiberius Brastaviceanu in 2006, after his description of the "filamentary ionization mode" (Sherbrooke University, 2005). In his Master's work he provided the empirical proof of the formation of filamentary distributions of solvated electrons in water, induced by high-power fs (femtosecond, one trillionth of a second) laser pulses in the self-focusing propagation regime, and described the theoretical context in which this phenomenon can be explained and controlled. Refer to main article on filament propagation.
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Solvation involves different types of intermolecular interactions: hydrogen bonding, ion-dipole interactions, and van der Waals forces (which consist of dipole-dipole, dipole-induced dipole, and induced dipole-induced dipole interactions). Which of these forces are at play depends on the molecular structure and properties of the solvent and solute. The similarity or complementary character of these properties between solvent and solute determines how well a solute can be solvated by a particular solvent. Nile red at daylight (top row) and UV-light (second row) in different solvents.
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Therefore, its conjugate base is suitable for the deprotonation of compounds with greater acidity, importantly, such weakly acidic compounds (carbon acids) of the type R2CHZ, where Z = C(O)R', CO2R' or CN. Conventional protic functional groups such as alcohols and carboxylic acids are of course readily deprotonated. Like most organolithium reagents, LDA is not a salt, but is highly polar. It forms aggregates in solution, with the extent of aggregation depending on the nature of the solvent. In THF its structure is primarily that of a solvated dimer.
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The proton is a "bare charge" with only about 1/64,000 of the radius of a hydrogen atom, and so is extremely reactive chemically. The free proton, thus, has an extremely short lifetime in chemical systems such as liquids and it reacts immediately with the electron cloud of any available molecule. In aqueous solution, it forms the hydronium ion, H3O+, which in turn is further solvated by water molecules in clusters such as [H5O2]+ and [H9O4]+. The transfer of in an acid–base reaction is usually referred to as "proton transfer".
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Atomic carbon is generated in the thermolysis of 5-diazotetrazole upon extrusion of 3 equivalents of dinitrogen: CN6 → :C: + 3N2 400x400px A clean source of atomic carbon can be obtained based on the thermal decomposition of tantalum carbide. In the developed source, carbon is loaded into a thin-walled tantalum tube. After being sealed, it is heated by direct electric current. The solvated carbon atoms diffuse to the outer surface of the tube and, when the temperature rises, the evaporation of atomic carbon from the surface of the tantalum tube is observed.
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It is isomorphous to uranocene and plutonocene, and they behave chemically identically: all three compounds are insensitive to water or dilute bases but are sensitive to air, reacting quickly to form oxides, and are only slightly soluble in benzene and toluene. Other known neptunium cyclooctatetraenyl derivatives include Np(RC8H7)2 (R = ethanol, butanol) and KNp(C8H8)·2THF, which is isostructural to the corresponding plutonium compound. In addition, neptunium hydrocarbyls have been prepared, and solvated triiodide complexes of neptunium are a precursor to many organoneptunium and inorganic neptunium compounds.
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Confinement of solvated ions in pores, such as those present in CDCs. As the pore size approaches the size of the solvation shell, the solvent molecules are removed, resulting in larger ionic packing density and increased charge storage capability. CDC electrodes have been shown to yield a gravimetric capacitance of up to 190 F/g in aqueous electrolytes and 180 F/g in organic electrolytes. The highest capacitance values are observed for matching ion/pore systems, which allow high-density packing of ions in pores in superionic states.
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As K+ passes through the pore, interactions between potassium ions and water molecules are prevented and the K+ interacts with specific atomic components of the Thr-Val-Gly-[YF]-Gly sequences from the four channel subunits . It may seem counterintuitive that a channel should allow potassium ions but not the smaller sodium ions through. However in an aqueous environment, potassium and sodium cations are solvated by water molecules. When moving through the selectivity filter of the potassium channel, the water-K+ interactions are replaced by interactions between K+ and carbonyl groups of the channel protein.
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Sample polymer brush A polymer brush is the name given to a surface coating consisting of polymers tethered to a surface. The brush may be either in a solvated state, where the tethered polymer layer consists of polymer and solvent, or in a melt state, where the tethered chains completely fill up the space available. These polymer layers can be tethered to flat substrates such as silicon wafers, or highly curved substrates such as nanoparticles. Also, polymers can be tethered in high density to another single polymer chain, although this arrangement is normally named a bottle brush.
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At typical ambient temperatures, sodium hypochlorite is more stable in dilute solutions that contain solvated and ions. The density of the solution is 1.093 g/mL at 5% concentration, and 1.21 g/mL at 14%, 20 °C.Environment Canada (1985): "Tech Info for Problem Spills: Sodium Hypochlorite (Draft)". Stoichiometric solutions are fairly alkaline, with pH 11 or higher since hypochlorous acid is a weak acid: : + HOCl + The following species and equilibria are present in solutions of : : (aq) ⇌ + : (aq) + + ⇌ (aq) + : (aq) + ⇌ : (aq) ⇌ (g) The second equilibrium equation above will be shifted to the right if the chlorine is allowed to escape as gas.
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Ions in their gas- like state are highly reactive and will rapidly interact with ions of opposite charge to give neutral molecules or ionic salts. Ions are also produced in the liquid or solid state when salts interact with solvents (for example, water) to produce solvated ions, which are more stable, for reasons involving a combination of energy and entropy changes as the ions move away from each other to interact with the liquid. These stabilized species are more commonly found in the environment at low temperatures. A common example is the ions present in seawater, which are derived from dissolved salts.
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The Brønsted–Lowry definition applies to other solvents, such as dimethyl sulfoxide: the solvent S acts as a base, accepting a proton and forming the conjugate acid SH+. A broader definition of acid dissociation includes hydrolysis, in which protons are produced by the splitting of water molecules. For example, boric acid, B(OH)3, , acts as a weak acid, even though it is not a proton donor, because of the hydrolysis equilibrium : + + H+. Similarly, metal ion hydrolysis causes ions such as to behave as weak acids: Section 9.1 "Acidity of Solvated Cations" lists many pKa values. : + .
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To design and characterize organic semiconductors used for optoelectronic applications one should first measure the absorption and photoluminescence spectra using commercial instrumentation. However, in order to find out if a material acts as an electron donor or acceptor one has to determine the energy levels for hole and electron transport. The easiest way of doing this, is to employ cyclic voltammetry. However, one has to take into account that using this technique the experimentally determined oxidation and reduction potential are lower bounds because in voltammetry the radical cations and anions are in a polar fluid solution and are, thus, solvated.
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QTAIM has also been applied to study the electron topology of solvated post-translational modifications to protein. For example, covalently bonded force constants in a set of lysine-arginine derived advanced glycation end-products were derived using the electronic structure calculations and then bond paths were used to illustrate differences in each of the applied computational chemistry functionals. Furthermore, QTAIM had been used to identify a bond path network of hydrogen bonds between glucosepane and nearby water molecules. In QTAIM the energy increase on decreasing the dihedral angle from 38° to 0° is a summation of several factors.
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A broader definition of acid dissociation includes hydrolysis, in which protons are produced by the splitting of water molecules. For example, boric acid (B(OH)3) produces H3O+ as if it were a proton donor, but it has been confirmed by Raman spectroscopy that this is due to the hydrolysis equilibrium: :B(OH)3 \+ 2 H2O B(OH)4− \+ H3O+. Similarly, metal ion hydrolysis causes ions such as [Al(H2O)6]3+ to behave as weak acids: Section 9.1 "Acidity of Solvated Cations" lists many pKa values. : [Al(H2O)6]3+ \+ H2O [Al(H2O)5(OH)]2+ \+ H3O+.
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Significant are also the extensions of the polaron concept: acoustic polaron, piezoelectric polaron, electronic polaron, bound polaron, trapped polaron, spin polaron, molecular polaron, solvated polarons, polaronic exciton, Jahn-Teller polaron, small polaron, bipolarons and many-polaron systems. These extensions of the concept are invoked, e. g., to study the properties of conjugated polymers, colossal magnetoresistance perovskites, high-T_{c} superconductors, layered MgB2 superconductors, fullerenes, quasi-1D conductors, semiconductor nanostructures. The possibility that polarons and bipolarons play a role in high-T_{c} superconductors has renewed interest in the physical properties of many-polaron systems and, in particular, in their optical properties.
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The trend may be different in other solvents. Higher ion aggregates, sometimes triples M+X−M+, sometimes dimers of ion pairs (M+X−)2, or even larger species can be identified in the Raman spectra of some liquid- ammonia solutions of Na+ salts by the presence of bands that cannot be attributed to either contact- or solvent-shared ion pairs. Evidence for the existence of fully solvated ion pairs in solution is mostly indirect, as the spectroscopic properties of such ion pairs are indistinguishable from those of the individual ions. Much of the evidence is based on the interpretation of conductivity measurements.
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Some methods are based on solutions to the Poisson–Boltzmann equation (PBE), often referred to as FDPB-based methods (FDPB is for "finite difference Poisson–Boltzmann"). The PBE is a modification of Poisson's equation that incorporates a description of the effect of solvent ions on the electrostatic field around a molecule. The H++ web server, the pKD webserver, MCCE, Karlsberg+, PETIT and GMCT use the FDPB method to compute pKa values of amino acid side chains. FDPB-based methods calculate the change in the pKa value of an amino acid side chain when that side chain is moved from a hypothetical fully solvated state to its position in the protein.
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Pseudocapacitance is accompanied with an electron charge-transfer between electrolyte and electrode coming from a de-solvated and adsorbed ion whereby only one electron per charge unit is participating. This faradaic charge transfer originates by a very fast sequence of reversible redox, intercalation or electrosorption processes. The adsorbed ion has no chemical reaction with the atoms of the electrode (no chemical bonds arise) since only a charge-transfer take place. A cyclic voltammogram shows the fundamental differences between static capacitance (rectangular) and pseudocapacitance (curved) The electrons involved in the faradaic processes are transferred to or from valence electron states (orbitals) of the redox electrode reagent.
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For example, ammonia solutions have a pH greater than 7 due to the reaction NH3 \+ H+ , which decreases the hydrogen cation concentration, which increases the hydroxide ion concentration. pOH can be kept at a nearly constant value with various buffer solutions. Schematic representation of the bihydroxide ion In aqueous solution the hydroxide ion is a base in the Brønsted–Lowry sense as it can accept a protonIn this context proton is the term used for a solvated hydrogen cation from a Brønsted–Lowry acid to form a water molecule. It can also act as a Lewis base by donating a pair of electrons to a Lewis acid.
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The cavity is lined with charged and polar residues that are likely solvated creating an energetically unfavorable environment for hydrophobic substrates and energetically favorable for polar moieties in amphiphilic compounds or sugar groups from LPS. Since the lipid cannot be stable for a long time in the chamber environment, lipid A and other hydrophobic molecules may "flip" into an energetically more favorable position within the outer membrane leaflet. The "flipping" may also be driven by the rigid-body shearing of the TMDs while the hydrophobic tails of the LPS are dragged through the lipid bilayer. Repacking of the helices switches the conformation into an outward-facing state.
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During the fission, the droplet loses a small percentage of its mass (1.0–2.3%) along with a relatively large percentage of its charge (10–18%). There are two major theories that explain the final production of gas-phase ions: the ion evaporation model (IEM) and the charge residue model (CRM). The IEM suggests that as the droplet reaches a certain radius the field strength at the surface of the droplet becomes large enough to assist the field desorption of solvated ions. The CRM suggests that electrospray droplets undergo evaporation and fission cycles, eventually leading progeny droplets that contain on average one analyte ion or less.
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DMol3 is a commercial (and academic) software package which uses density functional theory with a numerical radial function basis set to calculate the electronic properties of molecules, clusters, surfaces and crystalline solid materials from first principles. DMol3 can either use gas phase boundary conditions or 3d periodic boundary conditions for solids or simulations of lower-dimensional periodicity. It has also pioneered the use of the conductor- like screening model COSMO Solvation Model for quantum simulations of solvated molecules and recently of wetted surfaces. DMol3 permits geometry optimisation and saddle point search with and without geometry constraints, as well as calculation of a variety of derived properties of the electronic configuration.
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Water-in-water (W/W) emulsion is a system that consists of droplets of water- solvated molecules in another continuous aqueous solution; both the droplet and continuous phases contain different molecules that are entirely water- soluble. As such, when two entirely aqueous solutions containing different water-soluble molecules are mixed, water droplets containing predominantly one component are dispersed in water solution containing another component. Recently, such a water-in-water emulsion was demonstrated to exist and be stable from coalescence by the separation of different types of non- amphiphilic, but water-soluble molecular interactions. These molecular interactions include hydrogen bonding, pi stacking, and salt bridging.
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The way that both of these reactions are facilitated is by general acid-base catalysis which strengthen the oxygen nucleophile by removing bonded proteins and stabilizing the oxyanion leaving groups through protanation. It is also important to add that if a group is behaving as a base in the cleavage reaction then it must act as an acid in the ligation reaction. Solvated metal ions act in general acid-base catalysis, where the metal ions might act as a Lewis acid which polarize phosphate oxygen atoms. Another important factor in the rate of ligation reaction is the pH dependence which corresponds to a pKa of 5.6, which is not a factor in the cleavage reaction .
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The closing of the actin-binding cleft during the association reaction is structurally coupled with the opening of the nucleotide-binding pocket on the myosin active site. Notably, the final steps of ATP hydrolysis include the fast release of phosphate and the slow release of ADP. The release of a phosphate anion from bound ADP anion into water solution may be considered as an exergonic reaction because the phosphate anion has low molecular mass. Thus, we arrive at the conclusion that the primary release of the inorganic phosphate H2PO4− leads to transformation of a significant part of the free energy of ATP hydrolysis into the kinetic energy of the solvated phosphate, producing active streaming.
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The use of more polar solvents in the mobile phase will increase the retention time of analytes, whereas more hydrophobic solvents tend to induce faster elution (decreased retention times). Very polar solvents such as traces of water in the mobile phase tend to adsorb to the solid surface of the stationary phase forming a stationary bound (water) layer which is considered to play an active role in retention. This behavior is somewhat peculiar to normal phase chromatography because it is governed almost exclusively by an adsorptive mechanism (i.e., analytes interact with a solid surface rather than with the solvated layer of a ligand attached to the sorbent surface; see also reversed- phase HPLC below).
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Petek has developed coherent photoelectron spectroscopy and microscopy as methods for studying the dephasing and spatial propagation of polarization fields in solid state materials and nanostructure. He is developing methods for multidimensional multiphoton-photoemission spectroscopy. Together with Jin Zhao, Ken Jordan and Ken Onda, Petek also discovered wet electron states, where electrons are partially solvated by water and other protic solvents at molecule vacuum interfaces. Together with Min Feng and Jin Zhao, Petek discovered atom-like superatom states of C60, and similar hollow molecules. Petek’s research with Shijing Tan has involved studies of metal plasmon excitations with semiconductor substrates, where the charge injection from highly optically active plasmonic modes into semiconductor substrates could be used for solar energy harvesting.
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The extent of this type of ion pairing decreases as the size of the cation increases. Thus, solvent-shared ion pairs are characterized by a rather small shift of vibration frequency with respect to the "free" solvated anion, and the value of the shift is not strongly dependent on the nature of the cation. The shift for contact ion pairs is, by contrast, strongly dependent on the nature of the cation and decreases linearly with the ratio of the cations charge to the squared radius: :Cs+ > Rb+ > K+ > Na+ > Li+; :Ba2+ > Sr2+ > Ca2+. The extent of contact ion pairing can be estimated from the relative intensities of the bands due to the ion pair and free ion.
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The nature of NaCp depends strongly on its medium and for the purposes of planning syntheses, the reagent is often represented as a salt . Crystalline solvent-free NaCp, which is rarely encountered, is a "polydecker" sandwich complex, consisting of an infinite chain of alternating Na+ centers sandwiched between μ-η5:η5-C5H5 ligands. As a solution in donor solvents, NaCp is highly solvated, especially at the alkali metal as suggested by the isolability of the adduct Na(tmeda)Cp. In contrast to alkali metal cyclopentadienides, tetrabutylammonium cyclopentadienide (Bu4N+C5H5−) was found to be supported entirely by ionic bonding and its structure is representative of the structure of the cyclopentadienide anion (C5H5−, Cp−) in the solid state.
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Other hydrated forms, the Zundel cation , which is formed from a proton and two water molecules, and the Eigen cation , which is formed from a hydronium ion and three water molecules, are theorized to play an important role in the diffusion of protons though an aqueous solution according to the Grotthuss mechanism. Although the ion (aq) is often shown in introductory textbooks to emphasize that the hydron is never present as an unsolvated species in aqueous solution, it is somewhat misleading, as it oversimplifies infamously complex speciation of the solvated proton in water; the notation (aq) is often preferred, since it conveys aqueous solvation while remaining noncommittal with respect to the number of water molecules involved.
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A bare proton, , cannot exist in solution or in ionic crystals because of its unstoppable attraction to other atoms or molecules with electrons. Except at the high temperatures associated with plasmas, such protons cannot be removed from the electron clouds of atoms and molecules, and will remain attached to them. However, the term 'proton' is sometimes used loosely and metaphorically to refer to positively charged or cationic hydrogen attached to other species in this fashion, and as such is denoted "" without any implication that any single protons exist freely as a species. To avoid the implication of the naked "solvated proton" in solution, acidic aqueous solutions are sometimes considered to contain a less unlikely fictitious species, termed the "hydronium ion" ().
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Liquid ammonia is the best-known and most widely studied nonaqueous ionising solvent. Its most conspicuous property is its ability to dissolve alkali metals to form highly coloured, electrically conductive solutions containing solvated electrons. Apart from these remarkable solutions, much of the chemistry in liquid ammonia can be classified by analogy with related reactions in aqueous solutions. Comparison of the physical properties of NH3 with those of water shows NH3 has the lower melting point, boiling point, density, viscosity, dielectric constant and electrical conductivity; this is due at least in part to the weaker hydrogen bonding in NH3 and because such bonding cannot form cross-linked networks, since each NH3 molecule has only one lone pair of electrons compared with two for each H2O molecule.
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Standard Model of Elementary Particles The use of a directed neutrino beam allows the reconstruction of the initial neutrino energy and therefore total momentum transfer during the interaction. ANNIE examines the interactions between neutrinos and nuclei in water with the aim of producing measurements of final state neutron abundance as a function of total momentum transfer. Neutron capture is aided by the solvated gadolinium salts which have high neutron capture cross sections and emit around 8MeV in gamma radiation upon absorption of a thermalized neutron. Characterization of neutron yield in proton decay background events, which are predominantly encountered in atmospheric neutrino interactions in large water Cherenkov Detectors like Super-Kamiokande, would help increase confidence in the observation of proton-decay-like events.
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Due to the totally frictionless nature of the superfluid medium, the entire object then proceeds to act very much like a nanoscopic ball bearing, allowing effectively complete rotational freedom of the solvated chemical species. A quantum solvation shell consists of a region of non-superfluid helium-4 atoms that surround the molecule(s) and exhibit adiabatic following around the centre of gravity of the solute. As such, the kinetics of an effectively gaseous molecule can be studied without the need to use an actual gas (which can be impractical or impossible). It is necessary to make a small alteration to the rotational constant of the chemical species being examined, in order to compensate for the higher mass entailed by the quantum solvation shell.
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A sodium cation is solvated by water molecules with their partially negative charged lone pairs pointing inwards towards the positively charged sodium ion The hydration number, or solvation number of a compound is defined as the average number of molecules bound to the compound more strongly (by 13.3 kcal/mol or more) than they are bound to other water molecules. The hydration number is dependent on the concentration of the compound in solution, and the identity of the compound. When compounds are dissolved in water, the water molecules form a solvation shell surrounding the solute. For charged species, the orientation of water molecules around the solute is dependent on its ionic charge, with cations attracting water’s electronegative oxygen and anions attracting the hydrogens.
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Researchers have yet to fully characterize the solvation of hydronium ion in water, in part because many different meanings of solvation exist. A freezing-point depression study determined that the mean hydration ion in cold water is approximately : on average, each hydronium ion is solvated by 6 water molecules which are unable to solvate other solute molecules. Some hydration structures are quite large: the magic ion number structure (called magic because of its increased stability with respect to hydration structures involving a comparable number of water molecules – this is a similar usage of the word magic as in nuclear physics) might place the hydronium inside a dodecahedral cage. However, more recent ab initio method molecular dynamics simulations have shown that, on average, the hydrated proton resides on the surface of the cluster.
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Based on a simple theoretical model, in 1968 he proposed, in collaboration with Mordechai Bixon, the basic notions specifying the energy acquisition process, the interstate coupling modes, and the mechanisms of energy disposal were laid open. Subsequently, he developed the theory of molecular wavepacket dynamics and quantum beats. His contributions became seminal to the study of laser chemistry, multiphoton processes in molecules, relaxation phenomena in condensed phases and the dynamics of biophysical systems, and had an indelible impact on the modern development of chemical physics and theoretical chemistry. His research covers a vast range of fields, such as the theory of solvated electrons, properties of excited electronic states of molecules, coherent multiphoton processes, charge transfer in polar solvents and in biophysical systems and the dynamics of supercooled large molecules and of molecular clusters.
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Bases can exist in solution in liquid ammonia which cannot exist in aqueous solution: this is the case for any base which is stronger than the hydroxide ion but weaker than the amide ion. Many carbon anions can be formed in liquid ammonia solution by the action of the amide ion on organic molecules (see sodium amide for examples). The other extreme is a superacid, a medium in which the hydrogen ion is only very weakly solvated. The classic example is a mixture of antimony pentafluoride and liquid hydrogen fluoride: :SbF5 \+ HF ⇌ H+ \+ SbF6− The limiting base, the hexfluoroantimonate anion SbF6−, is so weakly attracted to the hydrogen ion that virtually any other base will bind more strongly: hence, this mixture can be used to protonate organic molecules which would not be considered bases in other solvents.
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Furthermore, they have higher melting points, hardnesses, and densities, and lower reactivities and solubilities in liquid ammonia, as well as having more covalent character in their compounds. Finally, the alkali metals are at the top of the electrochemical series, whereas the coinage metals are almost at the very bottom. The coinage metals' filled d shell is much more easily disrupted than the alkali metals' filled p shell, so that the second and third ionisation energies are lower, enabling higher oxidation states than +1 and a richer coordination chemistry, thus giving the group 11 metals clear transition metal character. Particularly noteworthy is gold forming ionic compounds with rubidium and caesium, in which it forms the auride ion (Au−) which also occurs in solvated form in liquid ammonia solution: here gold behaves as a pseudohalogen because its 5d106s1 configuration has one electron less than the quasi-closed shell 5d106s2 configuration of mercury.
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Dielectric constant is the most important factor in determining the occurrence of ion association. A table of some typical values can be found under Dielectric constant. Water has a relatively high dielectric constant value of 78.7 at 298K (25 °C), so in aqueous solutions at ambient temperatures 1:1 electrolytes such as NaCl do not form ion pairs to an appreciable extent except when the solution is very concentrated.Assuming that both Na+ and Cl− have 6 water molecules in the primary solvation shell at ambient temperatures, a 5 M solution (5 mol/L) will consist almost entirely of fully solvated ion pairs. 2:2 electrolytes (q1 = 2, q2 = 2) form ion pairs more readily. Indeed, the solvent-shared ion pair [Mg(H2O)6]2+SO42− was famously discovered to be present in seawater, in equilibrium with the contact ion pair [Mg(H2O)5(SO4)]Manfred Eigen, Nobel lecture.
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