Tungsten hexachloride
From Wikipedia, the free encyclopedia
| Tungsten hexachloride | |
|---|---|
 |
|
| IUPAC name | Tungsten(VI) chloride |
| Other names | Tungsten hexachloride |
| Identifiers | |
| CAS number | [13283-01-7] |
| RTECS number | YO7710000 |
| Properties | |
| Molecular formula | WCl6 |
| Molar mass | 396.61 g/mol |
| Appearance | dark blue crystals moisture sensitive |
| Density | 3.52 g/cm3 |
| Melting point |
275 °C |
| Boiling point |
346.7 °C |
| Solubility in water | hydrolyzes |
| Solubility in other solvents | chlorocarbons |
| Structure | |
| Crystal structure | α:rhombohedral, β: hexagonal |
| Coordination geometry |
octahedral |
| Dipole moment | 0 D |
| Hazards | |
| Main hazards | oxidizer hydrolysis releases HCl |
| R-phrases | 34 |
| S-phrases | 26-36/37/39-45 |
| Related compounds | |
| Related compounds | Molybdenum(V) chloride chromyl chloride tungsten hexafluoride |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references |
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Tungsten hexachloride is the chemical compound with the formula WCl6. This dark violet blue species exists as a volatile solid under standard conditions. It is an important starting reagent in the preparation of tungsten compounds.[1] WCl6 is a rare example of a charge neutral hexachloride, another example being ReCl6. MoCl6 cannot be prepared. Better known than WCl6 is the still more volatile WF6.
As a d0 ion, W(VI) forms diamagnetic derivatives. The hexachloride is octahedral with equivalent W-Cl distances of 2.24 - 2.26 Å.[2] In the WCl6, the chloride ligands are donors in both sigma- and pi sense. Methylation with trimethylaluminium affords hexamethyl tungsten. Treatment with butyl lithium affords a reagent that is useful for deoxygenation of epoxides.[3]
The chloride ligands in WCl6 can be replaced by many anionic ligands including Br−, NCS−, and RO− (R = alkyl, aryl).
[edit] Safety considerations
WCl6 is an aggressively corrosive oxidant and hydrolyzes to release hydrogen chloride.
[edit] References
- ^ J. W. Herndon "Tungsten(VI) Chloride” in Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette) 2004, J. Wiley & Sons, New York. DOI: 10.1002/047084289.
- ^ J. C. Taylor and P. W. Wilson "The structure of [beta]-tungsten hexachloride by powder neutron and X-ray diffraction" Acta Crystallographic (1974). B30, 1216-1220.doi:10.1107/S0567740874004572.
- ^ M. A. Umbreit, K. B. Sharpless (1990). "Deoxygenation of Epoxides with Lower Valent Tungsten Halides: trans-Cyclododecene". Org. Synth.; Coll. Vol. 7: 121.
