Titanium(IV) fluoride is the inorganic compound with the formulaTiF4. It is a white hygroscopic solid. In contrast to the other tetrahalides of titanium, it adopts a polymeric structure.[2] In common with the other tetrahalides, TiF4 is a strong Lewis acid.
Purification is by sublimation, which involves reversible cracking of the polymeric structure.[4]
X-ray crystallography reveals that the Ti centres are octahedral, but conjoined in an unusual columnar structure.[5]
Reactions
TiF4 forms adducts with many ligands. One example is the complex cis-TiF4(CH3CN)2, which is formed by treatment with acetonitrile.[6] It is also used as a reagent in the preparation of organofluorine compounds.[7] With fluoride, the cluster [Ti4F18]2- forms. It has an adamantane-like Ti4F6 core.[8]
Related to its Lewis acidity, TiF4 forms a variety of hexafluorides also called hexafluorotitanates. Hexafluorotitanic acid has been used commercially to clean metal surfaces. These salts are stable at pH<4 in the presence of hydrogen fluoride, otherwise they hydrolyze to give oxides.[3]
^Mazej, Zoran; Goreshnik, Evgeny (2009). "Poly[perfluorotitanate(IV)] Salts of [H3O]+, Cs+, [Me4N]+, and [Ph4P]+ and about the Existence of an Isolated [Ti2F9]− Anion in the Solid State". Inorganic Chemistry. 48 (14): 6918–6923. doi:10.1021/ic9009338. PMID19545141.