Beryllium hydroxide
Beryllium hydroxide, Be(OH)2, is an amphoteric hydroxide, dissolving in both acids and alkalis. Industrially, it is produced as a by-product in the extraction of beryllium metal from the ores beryl and bertrandite. The natural pure beryllium hydroxide is rare (in form of the mineral behoite, orthorhombic) or very rare (clinobehoite, monoclinic). When alkali is added to beryllium salt solutions the α-form (a gel) is formed. If this left to stand or boiled, the rhombic β-form precipitates. This has the same structure as zinc hydroxide, Zn(OH)2, with tetrahedral beryllium centers.
| Names | |
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| IUPAC name
Beryllium hydroxide | |
Other names
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| Identifiers | |
3D model (JSmol) |
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| ChEBI | |
| ChemSpider | |
| ECHA InfoCard | 100.033.048 |
| EC Number |
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| 1024 | |
| MeSH | Beryllium+hydroxide |
PubChem CID |
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| RTECS number |
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| UNII | |
CompTox Dashboard (EPA) |
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| Properties | |
| BeH2O2 | |
| Molar mass | 43.026 g·mol−1 |
| Appearance | Vivid white, opaque crystals |
| Density | 1.92 g cm−3 |
| Melting point | (decomposes) |
| 0.0000023965 g/L | |
Solubility product (Ksp) |
6.92×10−22 |
| Acidity (pKa) | 3.7 |
| Structure | |
| Linear | |
| Thermochemistry | |
Heat capacity (C) |
1.443 J K−1 |
Std molar entropy (S⦵298) |
47 J·mol−1·K−1 |
Std enthalpy of formation (ΔfH⦵298) |
-904 kJ mol−1 |
Gibbs free energy (ΔfG⦵) |
-818 kJ/mol |
| Hazards | |
| Occupational safety and health (OHS/OSH): | |
Main hazards |
Carcinogenic |
| GHS labelling: | |
| Danger | |
| NFPA 704 (fire diamond) | |
| Lethal dose or concentration (LD, LC): | |
LD50 (median dose) |
4 mg kg−1 (intravenous, rat) |
| NIOSH (US health exposure limits): | |
PEL (Permissible) |
TWA 0.002 mg/m3 C 0.005 mg/m3 (30 minutes), with a maximum peak of 0.025 mg/m3 (as Be) |
REL (Recommended) |
Ca C 0.0005 mg/m3 (as Be) |
IDLH (Immediate danger) |
Ca [4 mg/m3 (as Be)] |
| Related compounds | |
Related compounds |
Aluminium oxide |
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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