Titanium(IV) fluoride is the inorganic compound with the formula TiF4. It is a white hygroscopic solid. In contrast to the other tetrahalides of titanium, it adopts a polymeric structure. In common with the other tetrahalides, TiF4 is a strong Lewis acid. Preparation, structure, reactions The traditional method involves treatment of titanium tetrachloride with excess hydrogen fluoride: TiCl4 + 4 HF → TiF4 + 4 HCl Purification is by sublimation, which involves reversible cracking of the polymeric structure. X-ray crystallography reveals that the Ti centres are octahedral, but conjoined in an unusual columnar structure. TiF4 forms adducts with many ligands. One example is cis-TiF4(MeCN)2, which is formed by treatment with acetonitrile. References Fluorides Titanium halides Titanium(IV) compounds