Titanium tetrafluoride
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.[1] In common with the other tetrahalides, TiF4 is a strong Lewis acid.
Preparation and structure
The traditional method involves treatment of titanium tetrachloride with excess hydrogen fluoride:[2]
- TiCl4 + 4 HF → TiF4 + 4 HCl
Purification is by sublimation, which involves reversible cracking of the polymeric structure.[3] X-ray crystallography reveals that the Ti centres are octahedral, but conjoined in an unusual columnar structure.[4]
Reactions
TiF4 forms adducts with many ligands. One example is the complex cis-TiF4(CH3CN)2, which is formed by treatment with acetonitrile.[5] It is also used as a reagent in the preparation of organofluorine compounds.[6] With fluoride, the cluster [Ti4F18]2- forms. It has an adamantane-like Ti4F6 core.[7]
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.[2]
References
Template:Titanium compounds Template:Fluorides
- ↑ Script error: No such module "citation/CS1".
- ↑ a b Script error: No such module "citation/CS1".
- ↑ Handbook of Preparative Inorganic Chemistry, 2nd Ed. Edited by G. Brauer, Academic Press, 1963, NY. Vol. 1. p. 200.
- ↑ Script error: No such module "Citation/CS1".
- ↑ Script error: No such module "Citation/CS1".
- ↑ Script error: No such module "citation/CS1".
- ↑ Script error: No such module "Citation/CS1".