Zirconium(III) bromide
Chemical compound
From Wikipedia, the free encyclopedia
Zirconium(III) bromide is an inorganic compound with the formula ZrBr3.
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| Names | |
|---|---|
| IUPAC name
Zirconium tribromide | |
| Identifiers | |
3D model (JSmol) |
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| ChemSpider | |
PubChem CID |
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| Properties | |
| Br3Zr | |
| Molar mass | 330.936 g·mol−1 |
| Appearance | black |
| Structure | |
| Hexagonal | |
| P63/mcm, No. 193 | |
a = 6.728 Å, c = 6.299 Å α = 90°, β = 90°, γ = 120° | |
| Related compounds | |
Other anions |
Zirconium(III) chloride Zirconium(III) iodide |
Other cations |
Titanium(III) bromide Hafnium(III) bromide |
Related compounds |
Zirconium(IV) 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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Preparation
Almost all the trihalides of titanium, zirconium and hafnium can be prepared by the high-temperature reduction of the corresponding tetrahalide with the metal. Incomplete reaction and contamination of the product with excess metal often occurs.[1]
Zirconium(III) bromide can thus be prepared from zirconium(IV) bromide and zirconium foil.
- 3 ZrBr4 + Zr → 4 ZrBr3
Alternatively, zirconium(III) bromide crystallises from a solution of zirconium(III) in aluminium tribromide. The solution is prepared by reducing a eutectic solution of ZrBr4 in liquid AlBr3 at a temperature of 230–300 °C with metallic zirconium or aluminium.[2][3]
Structure and bonding
Zirconium(III) bromide has a lower magnetic moment than is expected for the d1 metal ion Zr3+, indicating non-negligible Zr-Zr bonding.[1]
The crystal structure of zirconium(III) bromide is based on hexagonal close packing of bromide ions with one third of the octahedral interstices occupied by Zr3+ ions.[1] The structure consists of parallel chains of face-sharing {ZrBr6} octahedra with equally spaced metal atoms. There is some elongation of the octahedra along the metal-metal axis, partly due to metal-metal repulsion.[3] ZrCl3, ZrBr3 and ZrI3 all adopt the β-TiCl3 structure,[1] but the elongation of octahedra is most pronounced in the chloride, moderate in the bromide and negligible in the iodide.[3]