{{chembox | Watchedfields = changed | verifiedrevid = 445720257 | ImageFile = Vanadium(II)-oxide-3D-vdW.png | ImageSize = 180px | IUPACName = Vanadium(II) oxide | OtherNames = Vanadium oxide |Section1={{Chembox Identifiers | CASNo_Ref = {{cascite|correct|CAS}} | CASNo = 12035-98-2 | ChEBI = 30044 | ChemSpiderID = 8139656 | EINECS = 234-834-3 | Gmelin = 532274 | PubChem = 24411 | StdInChI=1S/O.V/q-2;+2 | StdInChIKey = UQCOXNBRZHICQC-UHFFFAOYSA-N | SMILES = [V+2].[O-2] }} |Section2={{Chembox Properties | Formula = VO | MolarMass = 66.9409 g/mol | Appearance = grey solid with metallic lustre | Density = 5.758 g/cm<sup>3</sup> | Solubility = | MeltingPtC = 1789 | MeltingPt_notes = | BoilingPtC = 2627 | BoilingPt_notes = | pKa = | pKb = | RefractIndex = 1.5763 }} |Section3={{Chembox Structure | CrystalStruct = Halite (cubic), cF8 | SpaceGroup = Fm<u style="text-decoration:overline">3</u>m, No. 225 | Coordination = Octahedral (V<sup>2+</sup>)<br/>Octahedral (O<sup>2−</sup>) | LattConst_a = }} | Section4 = {{Chembox Thermochemistry | DeltaGf = −404.219 kJ/mol<ref name=usgs>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.</ref> | DeltaHc = | DeltaHf = −431.790 kJ/mol<ref name=usgs /> | Entropy = 39.01 J/mol·K<ref name=usgs /> | HeatCapacity = }} |Section7={{Chembox Hazards | ExternalSDS = | GHS_ref = <ref>{{Cite web |last=PubChem |title=Vanadium(II) oxide |url=https://pubchem.ncbi.nlm.nih.gov/compound/24411 |access-date=2026-02-03 |website=pubchem.ncbi.nlm.nih.gov |language=en}}</ref> | GHSPictograms = {{GHS07}}{{GHS08}} | GHSSignalWord = Danger | HPhrases = {{H-phrases|H319|H332|H335|H372}} | PPhrases = {{P-phrases|P260|P261|P264|P264+P265|P270|P271|P280|P304+P340|P305+P351+P338|P317|P319|P337+P317|P403+P233|P405|P501}} | MainHazards = | NFPA-H = | NFPA-F = | NFPA-R = | NFPA-S = | FlashPt = Non-flammable }} |Section8={{Chembox Related | OtherAnions = Vanadium monosulfide<br/>Vanadium monoselenide<br/>Vanadium monotelluride | OtherCations = Niobium(II) oxide<br/>Tantalum(II) oxide | OtherFunction = Vanadium(III) oxide<br/>Vanadium(IV) oxide<br/>Vanadium(V) oxide | OtherFunction_label = vanadium oxides | OtherCompounds = }} }}
'''Vanadium(II) oxide''' is the inorganic compound with the idealized formula VO. It is one of the several binary vanadium oxides. It adopts a distorted NaCl structure and contains weak V−V metal-to-metal bonds. VO is a semiconductor owing to delocalisation of electrons in the t<sub>2g</sub> orbitals. VO is a non-stoichiometric compound, its composition varying from VO<sub>0.8</sub> to VO<sub>1.3</sub>.<ref>{{Greenwood&Earnshaw2nd|page=982}}</ref>
Diatomic VO is one of the molecules found in the spectrum of relatively cool M-type stars.<ref>{{cite journal| last = Tsuji| first = T.| date = 1986| title = Molecules in Stars.| journal = Annu. Rev. Astron. Astrophys.| volume = 24| page = 94| bibcode = 1986ARA&A..24...89T| doi = 10.1146/annurev.aa.24.090186.000513}}</ref> A potential use of vanadium(II) monoxide is as a molecular vapor in synthetic chemical reagents in low-temperature matrices.<ref>{{Cite journal |last=Groshens |first=Thomas J. |last2=Klabunde |first2=Kenneth J. |date=August 1990 |title=Molecular vapor synthesis: the use of titanium monoxide and vanadium monoxide vapors as reagents |url=https://pubs.acs.org/doi/abs/10.1021/ic00341a025 |journal=Inorganic Chemistry |language=en |volume=29 |issue=16 |pages=2979–2982 |doi=10.1021/ic00341a025 |issn=0020-1669|url-access=subscription }}</ref>
==References== {{reflist}}
{{Vanadium compounds}} {{Oxides}}
Category:Vanadium(II) compounds Category:Non-stoichiometric compounds Category:Transition metal oxides Category:Rock salt crystal structure
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