Chromium(II) oxide

Chromium(II) oxide (CrO) is an inorganic compound composed of chromium and oxygen.^[1] It is a black powder that crystallises in the rock salt structure.^[2] Hypophosphites may reduce chromium(III) oxide to chromium(II) oxide:

H₃PO₂ + 2 Cr₂O₃ → 4 CrO + H₃PO₄

Chromium(II) oxide

Names
IUPAC name chromium(II) oxide
Identifiers
CAS Number	12018-00-7 Y
3D model (JSmol)	Interactive image
ChemSpider	2300900
PubChem CID	3037052
CompTox Dashboard (EPA)	DTXSID701314334 DTXSID20152717, DTXSID701314334
InChI InChI=1S/Cr.O Key: XVOFZWCCFLVFRR-UHFFFAOYSA-N
SMILES O=[Cr]
Properties
Chemical formula	CrO
Molar mass	67.996 g/mol
Appearance	black
Melting point	300 °C (572 °F; 573 K) (decomposes)
Structure
Crystal structure	cubic, cF8
Space group	Fm3m, No. 225
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

It is readily oxidized by the atmosphere. CrO is basic, while CrO₃ is acidic, and Cr₂O₃ is amphoteric.^[3]

CrO occurs in the spectra of luminous red novae, which occur when two stars collide. It is not known why red novae are the only objects that feature this molecule; one possible explanation is an as-yet-unknown nucleosynthesis process.^[4]

See also

• Chromium(IV) oxide
• Chromium(VI) oxide