Chromium(II) bromide
Chemical compound
From Wikipedia, the free encyclopedia
Chromium(II) bromide is the inorganic compound with the chemical formula CrBr2. Like many metal dihalides, CrBr2 adopts the "cadmium iodide structure" motif, i.e., it features sheets of octahedral Cr(II) centers interconnected by bridging bromide ligands. It is a white solid that dissolves in water to give blue solutions that are readily oxidized by air.
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| Names | |
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| IUPAC name
Chromium(II) bromide | |
Other names
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| Identifiers | |
3D model (JSmol) |
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CompTox Dashboard (EPA) |
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| Properties | |
| CrBr2 | |
| Molar mass | 211.804 g·mol−1 |
| Appearance | White solid[1] |
| Density | 4.236 g/cm3[1] |
| Melting point | 842 °C (1,548 °F; 1,115 K)[1] |
| soluble, exothermal blue solution[1] | |
| Structure | |
| monoclinic[1] | |
| Related compounds | |
Other anions |
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Related compounds |
Chromium(III) bromide |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Synthesis and reactions
It can be prepared by reduction of chromium(III) bromide with hydrogen gas for 6–10 hours at 350-400 °C, cogenerating hydrogen bromide:[2]
- 2 CrBr3 + H2 → 2 CrBr2 + 2 HBr
Treatment of chromium powder with concentrated hydrobromic acid gives a blue hydrated chromium(II) bromide, which can be converted to a related acetonitrile complex.[3]
- Cr + n H2O + 2 HBr → CrBr2(H2O)n + H2
