Vanadium(III) oxide

Vanadium(III) oxide is the inorganic compound with the formula V₂O₃. It is a black solid prepared by reduction of V₂O₅ with hydrogen or carbon monoxide.^[3][4] It is a basic oxide dissolving in acids to give solutions of vanadium (III) complexes.^[4] V₂O₃ has the corundum structure.^[4] It is antiferromagnetic with a critical temperature of 160 K, below which there is an abrupt change in conductivity from metallic to insulating.^[5] This also distorts the crystal structure to a monoclinic space group: C2/c.^[1]

Vanadium(III) oxide

Vanadium trioxide
Vanadium(III) oxide in a vial
Names
Other names Vanadium sesquioxide, Vanadic oxide
Identifiers
CAS Number	1314-34-7 Y
3D model (JSmol)	Interactive image
ECHA InfoCard	100.013.847
PubChem CID	518710
RTECS number	YW3050000
UNII	Y469L16CWH Y
CompTox Dashboard (EPA)	DTXSID90892259
SMILES [O-2].[V+3].[O-2].[V+3].[O-2]
Properties
Chemical formula	V2O3
Molar mass	149.881 g/mol
Appearance	Black powder
Density	4.87 g/cm3
Melting point	1,940 °C (3,520 °F; 2,210 K)
Solubility in other solvents	Insoluble
Magnetic susceptibility (χ)	+1976.0·10−6 cm3/mol
Structure[1]
Crystal structure	Corundum, hR30
Space group	R3c (No. 167)
Lattice constant	a = 547 pm α = 53.74°, β = 90°, γ = 90°
Thermochemistry
Std molar entropy (S⦵298)	98.07 J/mol·K [2]
Std enthalpy of formation (ΔfH⦵298)	−1218.800 kJ/mol [2]
Gibbs free energy (ΔfG⦵)	−1139.052 kJ/mol [2]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is YN ?) Infobox references

Upon exposure to air it gradually converts into indigo-blue V₂O₄.^[5]

In nature it occurs as the rare mineral karelianite.^[6]