Chromium(II) oxide
Chemical compound
From Wikipedia, the free encyclopedia
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]
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| Names | |
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| IUPAC name
chromium(II) oxide | |
| Identifiers | |
3D model (JSmol) |
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| ChemSpider | |
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CompTox Dashboard (EPA) |
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| Properties | |
| CrO | |
| Molar mass | 67.996 g/mol |
| Appearance | black |
| Melting point | 300 °C (572 °F; 573 K) (decomposes) |
| Structure | |
| cubic, cF8 | |
| Fm3m, No. 225 | |
| Related compounds | |
Related compounds |
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Properties
It is readily oxidized by the atmosphere. CrO is basic, while CrO3 is acidic, and Cr2O3 is amphoteric.[3]
Occurrence
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]
Preparation
Hypophosphites such as hypophosphorous acid can reduce chromium(III) oxide to chromium(II) oxide:
- H3PO2 + 2 Cr2O3 → 4 CrO + H3PO4
