Titanium tetrafluoride
Chemical compound
From Wikipedia, the free encyclopedia
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.[2] In common with the other tetrahalides, TiF4 is a strong Lewis acid.
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| Names | |
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| IUPAC name
Titanium(IV) fluoride | |
| Other names
Titanium tetrafluoride | |
| Identifiers | |
3D model (JSmol) |
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| ChemSpider | |
| ECHA InfoCard | 100.029.106 |
| EC Number |
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PubChem CID |
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| UNII | |
CompTox Dashboard (EPA) |
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| Properties | |
| TiF4 | |
| Molar mass | 123.861 g/mol |
| Appearance | white powder |
| Density | 2.798 g/cm3 |
| Melting point | 377 °C (711 °F; 650 K) |
| Boiling point | sublimes |
| Hazards | |
| GHS labelling:[1] | |
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| Danger | |
| H302, H312, H314, H332 | |
| P260, P264, P270, P271, P280, P301+P312, P301+P330+P331, P302+P352, P303+P361+P353, P304+P312, P304+P340, P305+P351+P338, P310, P312, P322, P330, P363, P405 | |
| NFPA 704 (fire diamond) | |
| Related compounds | |
Other anions |
Titanium(IV) bromide Titanium(IV) chloride Titanium(IV) iodide |
Related compounds |
Titanium(III) fluoride |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Preparation and structure
The traditional method involves treatment of titanium tetrachloride with excess hydrogen fluoride:[3]
- TiCl4 + 4 HF → TiF4 + 4 HCl
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]