Titanium tetrabromide is the chemical compound with the formula TiBr<sub>4</sub>. It is the most volatile transition metal bromide. The properties of TiBr<sub>4</sub> are an average of TiCl<sub>4</sub> and TiI<sub>4</sub>. Some key properties of these four-coordinated Ti(IV) species are their high Lewis acidity and their high solubility in nonpolar organic solvents. TiBr<sub>4</sub> is diamagnetic, reflecting the d<sup>0</sup> configuration of the metal centre.
This four-coordinated complex adopts a tetrahedral geometry. It can be prepared via several methods: (i) from the elements, (ii) via the reaction of TiO<sub>2</sub> with carbon and bromine (see Kroll process), and (iii) by treatment of TiCl<sub>4</sub> with HBr.
Titanium tetrabromide forms adducts such as TiBr<sub>4</sub>(THF)<sub>2</sub> and [TiBr<sub>5</sub>]<sup>âÂÂ</sup>. With bulky donor ligands, such as 2-methylpyridine (2-Mepy), five-coordinated adducts form. TiBr<sub>4</sub>(2-MePy) is trigonal bipyramidal with the pyridine in the equatorial plane.
TiBr<sub>4</sub> 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<sub>4âÂÂx</sub>Cl<sub>x</sub> (x = 0-4). The mechanism of this redistribution reaction is uncertain. One proposed pathway invokes the intermediacy of dimers.
TiBr<sub>4</sub> hydrolyzes rapidly, potentially dangerously, to release hydrogen bromide, otherwise known as hydrobromic acid.