Uranium pentabromide explained

Uranium pentabromide is an inorganic chemical compound with the formula .

Synthesis

The compound is made by reacting the elements in an acetonitrile solvent, or by reacting bromine with uranium metal or uranium tetrabromide at 55C.

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 80C into its constituent elements.^[3] The crystal structure is the same as that of β-, which is triclinic and consists of dimers.^[4]

Complexes

Stable complexes of the form are known with such ligands as triphenylphosphine oxide and hexamethylphosphoramide, and are obtained by brominating in the presence of the desired ligand.^[2] In addition, it is possible to obtain a hexabromouranate(V) salt by reacting with a monovalent bromide in thionyl bromide:^[1]

Notes and References

1. Book: Morss . L. R. . Edelstein . Norman M. . Fuger . Jean . The Chemistry of the Actinide and Transactinide Elements (Set Vol.1-6): Volumes 1-6 . 2010-10-21 . Springer Science & Business Media . 978-94-007-0211-0 . 526 . 29 May 2021 . en.
2. Brown . D. . Holah . D. G. . Rickard . C. E. F. . The stabilisation of plutonium tetrabromide and uranium pentabromide . Chemical Communications . 1968-01-01 . 11 . 651–652 . 10.1039/C19680000651 . en . 0009-241X.
3. The thermal decomposition and thermodynamic properties of uranium pentabromide . Journal of Inorganic and Nuclear Chemistry . 1973-11-01 . 35 . 11 . 3795–3803 . 10.1016/0022-1902(73)80071-5 . 29 May 2021 . en . 0022-1902. Blair . A. . Ihle . H. .
4. The crystal structure of uranium pentabromide by powder neutron diffraction . Journal of Inorganic and Nuclear Chemistry . 1978-01-01 . 40 . 6 . 1055–1057 . 10.1016/0022-1902(78)80507-7 . 29 May 2021 . en . 0022-1902. Levy . J.H. . Taylor . J.C. . Wilson . P.W. .