Vanadium(III) oxide

{{chembox

| Watchedfields = changed

| verifiedrevid = 414770347

| ImageFile = Kristallstruktur Aluminiumoxid.png

| ImageSize =

| ImageName = Vanadium trioxide

| OtherNames = Vanadium sesquioxide, Vanadic oxide

| ImageFile2 = File:Оксид ванадия(III).jpg

| ImageName2 = Vanadium(III) oxide in a vial

| ImageAlt2 = Vanadium(III) oxide

|Section1={{Chembox Identifiers

| CASNo = 1314-34-7

| CASNo_Ref = {{cascite|correct|CAS}}

| SMILES = [O-2].[V+3].[O-2].[V+3].[O-2]

| UNII_Ref = {{fdacite|correct|FDA}}

| UNII = Y469L16CWH

| PubChem = 518710

| RTECS = YW3050000

}}

|Section2={{Chembox Properties

| Formula = V₂O₃

| MolarMass = 149.881 g/mol

| Density = 4.87 g/cm³

| Solvent = other solvents

| SolubleOther = Insoluble

| MeltingPtC = 1940

| Appearance = Black powder

| MagSus = +1976.0·10⁻⁶ cm³/mol

}}

|Section3={{Chembox Structure

| Structure_ref = {{cite journal | last1=Shvets | first1=Petr | last2=Dikaya | first2=Olga | last3=Maksimova | first3=Ksenia | last4=Goikhman | first4=Alexander | title=A review of Raman spectroscopy of vanadium oxides | journal=Journal of Raman Spectroscopy | publisher=Wiley | volume=50 | issue=8 | date=2019-05-15 | issn=0377-0486 | doi=10.1002/jrs.5616 | pages=1226–1244| bibcode=2019JRSp...50.1226S | s2cid=182370875 }}

| CrystalStruct = Corundum, hR30

| SpaceGroup = R{{overline|3}}c (No. 167)

| LattConst_a = 547 pm

| LattConst_alpha = 53.74

}}

| Section4 = {{Chembox Thermochemistry

| DeltaGf = −1139.052 kJ/mol R. Robie, B. Hemingway, and J. Fisher, “Thermodynamic Properties of Minerals and Related Substances at 298.15K and 1bar Pressure and at Higher Temperatures,” US Geol. Surv., vol. 1452, 1978.[https://pubs.usgs.gov/bul/1452/report.pdf]

| DeltaHc =

| DeltaHf = −1218.800 kJ/mol

| Entropy = 98.07 J/mol·K

| HeatCapacity =

}}

}}

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.Handbook of Preparative Inorganic Chemistry, 2nd Ed. Edited by G. Brauer, Academic Press, 1963, NY. Vol. 1. p. 1267.{{Greenwood&Earnshaw}} It is a basic oxide dissolving in acids to give solutions of vanadium (III) complexes. V₂O₃ has the corundum structure. It is antiferromagnetic with a critical temperature of 160 K, below which there is an abrupt change in conductivity from metallic to insulating.E.M. Page, S.A.Wass (1994),Vanadium:Inorganic and Coordination chemistry, Encyclopedia of Inorganic Chemistry, John Wiley & Sons, {{ISBN|0-471-93620-0}} This also distorts the crystal structure to a monoclinic space group: C2/c.

Upon exposure to air it gradually converts into indigo-blue V₂O₄.

In nature it occurs as the rare mineral karelianite.{{Cite web|url=https://www.mindat.org/min-2158.html|title=Karelianite|website=www.mindat.org}}