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Reduction of this compound with alcohols gives the vanadium(IV) phosphates. These compounds are catalysts for the oxidation of butane to maleic anhydride . A key step in the activation of these catalysts is the conversion of VO(HPO 4 )•0.5H 2 O to the pyrophosphate (VO) 2 (P 2 O 7 ).
From left: [V(H 2 O) 6] 2+ (lilac), [V(H 2 O) 6] 3+ (green), [VO(H 2 O) 5] 2+ (blue) and [VO(H 2 O) 5] 3+ (yellow).. 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 ...
Organovanadium chemistry is the chemistry of organometallic compounds containing a carbon (C) to vanadium (V) chemical bond. [1] Organovanadium compounds find only minor use as reagents in organic synthesis but are significant for polymer chemistry as catalysts. [2] Oxidation states for vanadium are +2, +3, +4 and +5.
Vanadium(II) compounds are reducing agents, and vanadium(V) compounds are oxidizing agents. Vanadium(IV) compounds often exist as vanadyl derivatives, which contain the VO 2+ center. [23] Ammonium vanadate(V) (NH 4 VO 3) can be successively reduced with elemental zinc to obtain the different colors of vanadium in these four oxidation states.
The complexes [V(CN) 6] 3− and [V 2 Cl 9] 3− are referred to as hexacyanovanadate(III) and nonachlorodivanadate(III), respectively. A simple vanadate ion is the tetrahedral orthovanadate anion, VO 3− 4 (which is also called vanadate(V)), which is present in e.g. sodium orthovanadate and in solutions of V 2 O 5 in strong base ( pH > 13 [ 1
A general formula for such cyclic compounds is [HPO 3] x where x = number of phosphoric units in the molecule. When metaphosphoric acids lose their hydrogens as H +, cyclic anions called metaphosphates are formed. An example of a compound with such an anion is sodium hexametaphosphate (Na 6 P 6 O 18), used as a sequestrant and a food additive.
Vanadium(V) oxide (vanadia) is the inorganic compound with the formula V 2 O 5. Commonly known as vanadium pentoxide, it is a dark 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.
It is the predominant vanadium(V) species in acidic solutions with pH between 0 and 2, and its salts are formed by protonation of vanadium(V) oxide in such solutions: [2] [3] V 2 O 5 + 2 H + → 2 VO + 2 + H 2 O (K = 3.42 × 10 −2) The ion can form a complex with a single aminopolycarboxylate ligand, [4] or with tridentate Schiff base ligands ...