Chromium(III) oxide
Chromium(III) oxide (or chromia) is an inorganic compound with the formula Cr
2O
3. It is one of the principal oxides of chromium and is used as a pigment. In nature, it occurs as the rare mineral eskolaite.
| Names | |
|---|---|
| Other names | |
| Identifiers | |
3D model (JSmol) |
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| ChEBI | |
| ChemSpider | |
| ECHA InfoCard | 100.013.783 |
| EC Number |
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| 11116 | |
PubChem CID |
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| RTECS number |
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| UNII | |
| UN number | 3077 |
CompTox Dashboard (EPA) |
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| Properties | |
| Cr2O3 | |
| Molar mass | 151.9904 g/mol |
| Appearance | light to dark green, fine crystals |
| Density | 5.22 g/cm3 |
| Melting point | 2,435 °C (4,415 °F; 2,708 K) |
| Boiling point | 4,000 °C (7,230 °F; 4,270 K) |
| insoluble | |
| Solubility in alcohol | insoluble in alcohol, acetone, acids |
| +1960.0×10−6 cm3/mol | |
Refractive index (nD) |
2.551 |
| Structure | |
| Corundum | |
| R3c (No. 167) | |
a = 495 pm, c = 1358 pm | |
| Thermochemistry | |
Std molar entropy (S⦵298) |
81 J·mol−1·K−1 |
Std enthalpy of formation (ΔfH⦵298) |
−1128 kJ·mol−1 |
| Hazards | |
| GHS labelling: | |
| Danger | |
| H302, H317, H319, H360 | |
| P201, P202, P261, P264, P270, P272, P280, P281, P301+P312, P302+P352, P305+P351+P338, P308+P313, P321, P330, P333+P313, P337+P313, P363, P405, P501 | |
| NIOSH (US health exposure limits): | |
PEL (Permissible) |
TWA 1 mg/m3 |
REL (Recommended) |
TWA 0.5 mg/m3 |
IDLH (Immediate danger) |
250 mg/m3 |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references | |
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