Vanadium(III) oxide

Vanadium(III) oxide
Other names Vanadium sesquioxide, Vanadic oxide
Identifiers
CAS number	1314-34-7 Y
PubChem	518710
RTECS number	YW3050000
Properties
Molecular formula	V2O3
Molar mass	149.881 g/mol
Appearance	Black powder
Density	4.87 g/cm3
Melting point	1940 °C
Solubility in other solvents	Insoluble
Structure
Crystal structure	Trigonal (karelianite), hR30
Space group	R-3c h, No. 167
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Vanadium trioxide is the chemical compound V₂O₃. It is prepared by reduction of V₂O₅ with hydrogen or carbon monoxide.^[1]It is a basic oxide dissolving in acids to give reducing vanadium(III) solutions.^[1] V₂O₃ has the corundum structure.^[1] It is antiferromagnetic with a critical temperature of 160 K. ^[2] At this temperature there is an abrupt change in conductivity from metallic to insulating.^[2]

On exposure to air it is gradually converted into indigo-blue crystals of V₂O₄.^[2] Vanadium trioxide is generally used as a catalyst when making ethanol from ethylene.^{[citation needed]}

In nature it occurs only rarely, as the mineral karelianite.

References

1. ^ ^{a b c} Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Oxford: Butterworth-Heinemann. ISBN 0080379419. 
2. ^ ^{a b c} E.M. Page, S.A.Wass (1994),Vanadium:Inorganic and Coordination chemistry, Encyclopedia of Inorganic Chemistry, John Wiley & Sons, ISBN 0-471-93620-0