Titanium tetrabromide is the chemical compound with the formula TiBr₄. It is the most volatile transition metal bromide. The properties of TiBr₄ are an average of TiCl₄ and TiI₄. Some key properties of these four-coordinated Ti(IV) species are their high Lewis acidity and their high solubility in nonpolar organic solvents. TiBr₄ is diamagnetic, reflecting the d⁰ configuration of the metal centre.

Preparation and structure

This four-coordinated complex adopts a tetrahedral geometry. It can be prepared via several methods: (i) from the elements, (ii) via the reaction of TiO₂ with carbon and bromine (see

Kroll process The Kroll process is a pyrometallurgical industrial process used to produce metallic titanium from titanium tetrachloride. The Kroll process replaced the Hunter process for almost all commercial production. Process In the Kroll process, the TiCl ...

), and (iii) by treatment of TiCl₄ with HBr.

Reactions

Titanium tetrabromide forms adducts such as TiBr₄( THF)₂ and iBr₅sup>−. With bulky donor ligands, such as 2-methylpyridine (2-Mepy), five-coordinated adducts form. TiBr₄(2-MePy) is trigonal bipyramidal with the pyridine in the equatorial plane. TiBr₄ has been used as a Lewis-acid catalyst in organic synthesis. The tetrabromide and tetrachlorides of titanium react to give a statistical mixture of the mixed tetrahalides, TiBr_4−xCl_x (x = 0-4). The mechanism of this redistribution reaction is uncertain. One proposed pathway invokes the intermediacy of dimers.

Safety

TiBr₄ hydrolyzes rapidly, potentially dangerously, to release hydrogen bromide, otherwise known as hydrobromic acid.

References

{{bromine compounds Bromides Titanium halides Titanium(IV) compounds