9921. Vanadium Pentoxide

Nomenclature

CAS number: 1314-62-1
Vanadium oxide (V2O5); vanadic anhydride.
O5V2; mol wt 181.88.
O 43.98%, V 56.02%.
V2O5.

Description and references

Prepd by heating ammonium metavanadate, NH4VO3.

Properties

Yellow to rust-brown orthorhombic crystals; d 3.35; mp 690°. Poisonous. Loses oxygen reversibly in the region 700-1125°. One gram dissolves in ≈125 ml water; sol in concd acids, forming red to yellow solns; sol in alkalies, forming vanadates; insol in alcohol. Its acid solutions are reduced by SO2, Zn + HCl, and by evaporation with HCl.

Caution

Reported to be a respiratory irritant and to cause skin pallor, greenish-black tongue, chest pain, cough, dyspnea, palpitation, lung changes. When ingested, causes G.I. disturbances. May also cause a papular skin rash: Zenz et al., Arch. Environ. Health 5, 542 (1962); E. Browning, Toxicity of Industrial Metals (Appleton-Century-Crofts, New York, 2nd ed., 1969) pp 340-347.

Use

As catalyst in the oxidation of SO2 to SO3, alcohol to acetaldehyde, etc.; for the manuf of yellow glass; inhibiting ultraviolet light transmission in glass; depolarizer; as developer in photography; in form of ammonium vanadate as mordant in dyeing and printing fabrics and in manuf of aniline black.