Uranium pentabromide
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| Identifiers | |
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PubChem CID
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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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Uranium pentabromide is an inorganic chemical compound with the formula U2Br10.
Synthesis
[edit]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
[edit]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 its constituent elements.[3] The crystal structure is the same as that of β-UCl5, which is triclinic and consists of U2Br10 dimers.[4]
Complexes
[edit]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]−
References
[edit]- ^ a b c Morss, L. R.; Edelstein, Norman M.; Fuger, Jean (2010-10-21). The Chemistry of the Actinide and Transactinide Elements (Set Vol.1-6): Volumes 1-6. Springer Science & Business Media. p. 526. ISBN 978-94-007-0211-0. Retrieved 29 May 2021.
- ^ a b Brown, D.; Holah, D. G.; Rickard, C. E. F. (1968-01-01). "The stabilisation of plutonium tetrabromide and uranium pentabromide". Chemical Communications (11): 651–652. doi:10.1039/C19680000651. ISSN 0009-241X.
- ^ Blair, A.; Ihle, H. (1973-11-01). "The thermal decomposition and thermodynamic properties of uranium pentabromide". Journal of Inorganic and Nuclear Chemistry. 35 (11): 3795–3803. doi:10.1016/0022-1902(73)80071-5. ISSN 0022-1902. Retrieved 29 May 2021.
- ^ Levy, J.H.; Taylor, J.C.; Wilson, P.W. (1978-01-01). "The crystal structure of uranium pentabromide by powder neutron diffraction". Journal of Inorganic and Nuclear Chemistry. 40 (6): 1055–1057. doi:10.1016/0022-1902(78)80507-7. ISSN 0022-1902. Retrieved 29 May 2021.