Vanadium is a chemical element; it has symbol V and atomic number 23. It is a hard, silvery-grey, malleable transition metal. The elemental metal is rarely found in nature, but once isolated artificially, the formation of an oxide layer (passivation) somewhat stabilizes the free metal against further oxidation.
1,10-Phenanthroline (phen) is a heterocyclic organic compound. It is a white solid that is soluble in organic solvents. The 1,10 refer to the location of the nitrogen atoms that replace CH's in the hydrocarbon called phenanthrene.
Vanadium(V) oxide (vanadia) is the inorganic compound with the formula V2O5. Commonly known as vanadium pentoxide, it is a brown/yellow solid, although when freshly precipitated from aqueous solution, its colour is deep orange. Because of its high oxidation state, it is both an amphoteric oxide and an oxidizing agent. From the industrial perspective, it is the most important compound of vanadium, being the principal precursor to alloys of vanadium and is a widely used industrial catalyst.
The vanadium redox battery (VRB), also known as the vanadium flow battery (VFB) or vanadium redox flow battery (VRFB), is a type of rechargeable flow battery. It employs vanadium ions as charge carriers. The battery uses vanadium's ability to exist in a solution in four different oxidation states to make a battery with a single electroactive element instead of two. For several reasons, including their relative bulkiness, vanadium batteries are typically used for grid energy storage, i.e., attached to power plants/electrical grids.
A flow battery, or redox flow battery, is a type of electrochemical cell where chemical energy is provided by two chemical components dissolved in liquids that are pumped through the system on separate sides and in opposite direction of a membrane. Ion transfer inside the cell occurs through the membrane while both liquids circulate in their own respective space. Cell voltage is chemically determined by the Nernst equation and ranges, in practical applications, from 1.0 to 2.43 volts. The energy capacity is a function of the electrolyte volume and the power is a function of the surface area of the electrodes.
In chemistry, a vanadate is an anionic coordination complex of vanadium. Often vanadate refers to oxoanions of vanadium, most of which exist in its highest oxidation state of +5. The complexes [V(CN)6]3− and [V2Cl9]3− are referred to as hexacyanovanadate(III) and nonachlorodivanadate(III), respectively.
Vanadium(III) chloride describes the inorganic compound with the formula VCl3 and its hydrates. It forms a purple anhydrous form and a green hexahydrate [VCl2(H2O)4]Cl·2H2O. These hygroscopic salts are common precursors to other vanadium(III) complexes and is used as a mild reducing agent.
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 (~68 °C (341 K)). Electrical resistivity, opacity, etc, can change up several orders. Owing to these properties, it has been used in surface coating, sensors, and imaging. Potential applications include use in memory devices, phase-change switches, passive radiative cooling applications, such as smart windows and roofs, that cool or warm depending on temperature, aerospace communication systems and neuromorphic computing.
Vanadyl(IV) sulfate describes a collection of inorganic compounds of vanadium with the formula, VOSO4(H2O)x where 0 ≤ x ≤ 6. The pentahydrate is common. This hygroscopic blue solid is one of the most common sources of vanadium in the laboratory, reflecting its high stability. It features the vanadyl ion, VO2+, which has been called the "most stable diatomic ion".
Vanadium compounds are compounds formed by the element vanadium (V). The chemistry of vanadium is noteworthy for the accessibility of the four adjacent oxidation states 2–5, whereas the chemistry of the other group 5 elements, niobium and tantalum, are somewhat more limited to the +5 oxidation state. In aqueous solution, vanadium forms metal aquo complexes of which the colours are lilac [V(H2O)6]2+, green [V(H2O)6]3+, blue [VO(H2O)5]2+, yellow-orange oxides [VO(H2O)5]3+, the formula for which depends on pH. Vanadium(II) compounds are reducing agents, and vanadium(V) compounds are oxidizing agents. Vanadium(IV) compounds often exist as vanadyl derivatives, which contain the VO2+ center.
The vanadyl or oxovanadium(IV) cation, VO2+, is a functional group that is common in the coordination chemistry of vanadium. Complexes containing this functional group are characteristically blue and paramagnetic. A triple bond is proposed to exist between the V4+ and O2− centers. The description of the bonding in the vanadyl ion was central to the development of modern ligand-field theory.
In chemistry, a (redox) non-innocent ligand is a ligand in a metal complex where the oxidation state is not clear. Typically, complexes containing non-innocent ligands are redox active at mild potentials. The concept assumes that redox reactions in metal complexes are either metal or ligand localized, which is a simplification, albeit a useful one.
Zinc compounds are chemical compounds containing the element zinc which is a member of the group 12 of the periodic table. The oxidation state of zinc in most compounds is the group oxidation state of +2. Zinc may be classified as a post-transition main group element with zinc(II). Zinc compounds are noteworthy for their nondescript appearance and behavior: they are generally colorless, do not readily engage in redox reactions, and generally adopt symmetrical structures.
Rhodocene is a chemical compound with the formula [Rh(C5H5)2]. Each molecule contains an atom of rhodium bound between two planar aromatic systems of five carbon atoms known as cyclopentadienyl rings in a sandwich arrangement. It is an organometallic compound as it has (haptic) covalent rhodium–carbon bonds. The [Rh(C5H5)2] radical is found above 150 °C (302 °F) or when trapped by cooling to liquid nitrogen temperatures (−196 °C [−321 °F]). At room temperature, pairs of these radicals join via their cyclopentadienyl rings to form a dimer, a yellow solid.
Metal acetylacetonates are coordination complexes derived from the acetylacetonate anion (CH
3COCHCOCH−
3) and metal ions, usually transition metals. The bidentate ligand acetylacetonate is often abbreviated acac. Typically both oxygen atoms bind to the metal to form a six-membered chelate ring. The simplest complexes have the formula M(acac)3 and M(acac)2. Mixed-ligand complexes, e.g. VO(acac)2, are also numerous. Variations of acetylacetonate have also been developed with myriad substituents in place of methyl (RCOCHCOR′−). Many such complexes are soluble in organic solvents, in contrast to the related metal halides. Because of these properties, acac complexes are sometimes used as catalyst precursors and reagents. Applications include their use as NMR "shift reagents" and as catalysts for organic synthesis, and precursors to industrial hydroformylation catalysts. C
5H
7O−
2 in some cases also binds to metals through the central carbon atom; this bonding mode is more common for the third-row transition metals such as platinum(II) and iridium(III).
Vanadyl acetylacetonate is the chemical compound with the formula VO(acac)2, where acac– is the conjugate base of acetylacetone. It is a blue-green solid that dissolves in polar organic solvents. The coordination complex consists of the vanadyl group, VO2+, bound to two acac– ligands via the two oxygen atoms on each. Like other charge-neutral acetylacetonate complexes, it is not soluble in water.
In chemistry, metal aquo complexes are coordination compounds containing metal ions with only water as a ligand. These complexes are the predominant species in aqueous solutions of many metal salts, such as metal nitrates, sulfates, and perchlorates. They have the general stoichiometry [M(H2O)n]z+. Their behavior underpins many aspects of environmental, biological, and industrial chemistry. This article focuses on complexes where water is the only ligand, but of course many complexes are known to consist of a mix of aquo and other ligands.
Vanadyl perchlorate or vanadyl triperchlorate is a golden yellow coloured liquid or crystalline compound of vanadium, oxygen and perchlorate group. The substance consists of molecules covalently bound and is quite volatile; it ignites organic solvents on contact and explodes at temperatures above 80 °C.
Vanadium phosphates are inorganic compounds with the formula VOxPO4 as well related hydrates with the formula VOxPO4(H2O)n. Some of these compounds are used commercially as catalysts for oxidation reactions.
Transition metal thioether complexes comprise coordination complexes of thioether (R2S) ligands. The inventory is extensive.
