Chromium(III) hydroxide
Chemical compound (Cr(OH)3)
From Wikipedia, the free encyclopedia
Chromium(III) hydroxide is a gelatinous green inorganic compound with the chemical formula Cr(OH)3. It is a polymer with an undefined structure and low solubility. It is amphoteric, dissolving in both strong alkalis and strong acids.[2]
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| Names | |
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| IUPAC name
Chromium(3+) hydroxide | |
| Identifiers | |
3D model (JSmol) |
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| ChemSpider | |
| ECHA InfoCard | 100.013.781 |
PubChem CID |
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CompTox Dashboard (EPA) |
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| Properties | |
| Cr(OH)3 | |
| Molar mass | 103.017 g·mol−1 |
| Appearance | green, gelatinous precipitate |
| Density | 3.11 g/cm3 |
| insoluble | |
| Hazards | |
| NIOSH (US health exposure limits): | |
PEL (Permissible) |
TWA 1 mg/m3[1] |
REL (Recommended) |
TWA 0.5 mg/m3[1] |
IDLH (Immediate danger) |
250 mg/m3[1] |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Preparation
Chromium(III) hydroxide is prepared by treating an aqueous solution of hydrated chromium trichloride with ammonia.[3]
It can also be prepared by treating an aqueous solution of chromium(III) nitrate with potassium hydroxide until the pH is within 7 to 8:[4] The following idealized equation suffices:
- Cr(NO3)3 + 3 KOH → Cr(OH)3 + 3 KNO3
