Chemical compound

Zirconium(IV) bromide is the inorganic compound with the formula ZrBr4. This colourless solid is the principal precursor to other Zr–Br compounds.

Preparation and properties

ZrBr4 is prepared by the action of bromine on zirconium oxide via a carbothermic reaction:[1]

ZrO2 + 2 C + 2 Br2 → ZrBr4 + 2 CO

Like many related tetrahalides, it is purified by sublimation.

It can also be prepared by treatment of the borohydride complex with hydrogen bromide:[2]

Zr(BH4)4 + 4 HBr → ZrBr4 + 4 H2 + 2 B2H6

Like related tetrabromides of Ti and Hf, ZrBr4 hydrolyzes readily to give oxy-bromide, with release of hydrogen bromide.

Structure

No single crystal X-ray study of ZrBr4 has been described. Some reports suggest that it is isostructural with TiCl4 and TiBr4, featuring tetrahedral metal centers.[3] Other studies indicate a polymeric structure.[4] ZrCl4 is polymeric in the solid state, featuring octahedral Zr centers.[5]

References

  1. ^ R. C. Young, Hewitt G. Fletcher, "Anhydrous Zirconium Tetrabromide" Inorganic Syntheses, 1939, vol. 1, pp. 49–51. doi:10.1002/9780470132326.ch18
  2. ^ Calderazzo, Fausto; Pallavicini, Piersandro; Pampaloni, Guido (1990). "Arene derivatives of zirconium(II) and hafnium(II)". Journal of the Chemical Society, Dalton Transactions (6): 1813. doi:10.1039/DT9900001813.
  3. ^ Berdonosov, S. S.; Lapitskii, A. V. (1963). "Structure of Zr and Hf Tetrabromides". Vestnik Moskovskogo Universiteta, Seriya 2: Khimiya. 18: 42–4. (from abstract): The structure was assumed to be similar to that of SnI4 ... was verified by comparing exptl. and calcd. line intensities, by using Cu K radiation for powder patterns. ... Based on the value of the radius of the I- ion, the lattice parameter and the theoretical sp. gravity of ZrI4 and HfI4 were calcd.{{cite journal}}: CS1 maint: uses authors parameter (link)
  4. ^ Carter, J. C.; Smith, J. A. S. (1974). "Nuclear quadrupole resonance in hafnium and zirconium tetrabromide". Journal of the Chemical Society, Chemical Communications (20): 835–6. doi:10.1039/c39740000835.{{cite journal}}: CS1 maint: uses authors parameter (link)
  5. ^ A. F. Wells (1984). Structural Inorganic Chemistry. Oxford: Clarendon Press. ISBN 0-19-855370-6.