Titanium tetrabromide
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| Names | |
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| IUPAC name
Titanium(IV) bromide
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| Other names
Titanium tetrabromide
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| Identifiers | |
3D model (JSmol)
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PubChem CID
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| Properties | |
| TiBr4 | |
| Molar mass | 367.483 g/mol |
| Appearance | brown crystals hygroscopic |
| Density | 3.25 g/cm3 |
| Melting point | 39 °C (102 °F; 312 K) |
| Boiling point | 230 °C (446 °F; 503 K) |
| hydrolyses | |
| Solubility in other solvents | chlorocarbons, benzene |
| Structure | |
| cubic, Pa3, Z = 8 | |
| Tetrahedral | |
| 0 D | |
| Hazards | |
| Occupational safety and health (OHS/OSH): | |
Main hazards
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corrosive |
| GHS labelling:[1] | |
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| Danger | |
| H314 | |
| P260, P264, P280, P301+P330+P331, P303+P361+P353, P304+P340, P305+P351+P338, P310, P363, P405 | |
| NFPA 704 (fire diamond) | <imagemap>
File:NFPA 704.svg|80px|alt=NFPA 704 four-colored diamond poly 150 150 300 300 150 450 0 300 Health 3: Short exposure could cause serious temporary or residual injury. E.g. chlorine gas poly 300 0 450 150 300 300 150 150 Flammability 0: Will not burn. E.g. water poly 450 150 600 300 450 450 300 300 Instability 1: Normally stable, but can become unstable at elevated temperatures and pressures. E.g. calcium poly 300 300 450 450 300 600 150 450 Special hazards (white): no code desc none </imagemap> |
| Flash point | Non-flammable |
| Related compounds | |
Other anions
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Titanium(IV) chloride Titanium(IV) fluoride Titanium(IV) iodide |
Related compounds
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Titanium(III) bromide |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Titanium tetrabromide is the chemical compound with the formula TiBr4. It is the most volatile transition metal bromide. The properties of TiBr4 are an average of TiCl4 and TiI4. Some key properties of these four-coordinated Ti(IV) species are their high Lewis acidity and their high solubility in nonpolar organic solvents. TiBr4 is diamagnetic, reflecting the d0 configuration of the metal centre.[2]
Preparation and structure
This four-coordinated complex adopts a tetrahedral geometry. It can be prepared via several methods: (i) from the elements, (ii) via the reaction of TiO2 with carbon and bromine (see Kroll process), and (iii) by treatment of TiCl4 with HBr.
Reactions
Titanium tetrabromide forms adducts such as TiBr4(THF)2 and [TiBr5]−.[3] With bulky donor ligands, such as 2-methylpyridine (2-Mepy), five-coordinated adducts form. TiBr4(2-MePy) is trigonal bipyramidal with the pyridine in the equatorial plane.[4]
TiBr4 has been used as a Lewis-acid catalyst in organic synthesis.[5]
The tetrabromide and tetrachlorides of titanium react to give a statistical mixture of the mixed tetrahalides, TiBr4−xClx (x = 0-4). The mechanism of this redistribution reaction is uncertain. One proposed pathway invokes the intermediacy of dimers.[6]
Safety
TiBr4 hydrolyzes rapidly, potentially dangerously, to release hydrogen bromide, otherwise known as hydrobromic acid.
References
- ^ "Titanium tetrabromide". pubchem.ncbi.nlm.nih.gov. Retrieved 12 December 2021.
- ^ Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5.
- ^ Colin S. Creaser & J. Alan Creighton (1975). "Pentachloro- and pentabromo-titanate(IV) ions". J. Chem. Soc., Dalton Trans. (14): 1402–1405. doi:10.1039/DT9750001402.
- ^ Hensen, K.; Lemke, A.; Bolte, M. (2000). "Tetrabromo(2-methylpyridine-N)-titanate(IV)". Acta Crystallographica. C56 (12): e565–e566. Bibcode:2000AcCrC..56E.565H. doi:10.1107/S0108270100015407.
- ^ B. Patterson, S. Marumoto & S. D. Rychnovsky (2003). "Titanium(IV)-Promoted Mukaiyama Aldol-Prins Cyclizations". Org. Lett. 5 (17): 3163–3166. doi:10.1021/ol035303n. PMID 12917007.
- ^ S. P. Webb & M. S. Gordon (1999). "Intermolecular Self-Interactions of the Titanium Tetrahalides TiX4 (X = F, Cl, Br)". J. Am. Chem. Soc. 121 (11): 2552–2560. doi:10.1021/ja983339i.