Uranium pentabromide
Chemical compound
From Wikipedia, the free encyclopedia
Uranium pentabromide is an inorganic chemical compound with the formula U2Br10.
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3D model (JSmol) |
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CompTox Dashboard (EPA) |
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| Properties | |
| UBr5 | |
| Molar mass | 637.549 g/mol |
| Appearance | dark brown, hygroscopic crystalline solid |
| decomposes | |
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
The compound is made by reacting the elements in an acetonitrile solvent, or by reacting bromine with uranium metal or uranium tetrabromide at 55 °C (131 °F; 328 K).[1]
Properties
Uranium pentabromide is a hygroscopic dark brown solid that decomposes in water and most organic solvents, the exceptions being acetonitrile or dichloromethane.[1] The compound is rather unstable and difficult to purify,[2] decomposing at 80 °C (176 °F; 353 K) into uranium tetrabromide and bromine.[3] The crystal structure is the same as that of β-UCl5, which is triclinic and consists of U2Br10 dimers.[4]
Complexes
Stable complexes of the form UBr5L are known with such ligands as triphenylphosphine oxide and hexamethylphosphoramide, and are obtained by brominating UBr4 in the presence of the desired ligand.[2] In addition, it is possible to obtain a hexabromouranate(V) salt by reacting UBr5 with a monovalent bromide in thionyl bromide:[1]
- U2Br10 + 2MBr → 2M+[UBr6]−