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Tungsten hexachloride



Tungsten hexachloride
General
Systematic name Tungsten(VI) chloride
Other names Tungsten hexachloride
Molecular formula WCl6
Molar mass 396.61 g/mol
Appearance dark blue crystals
moisture sensitive
CAS number [13283-01-7]
Properties
Density and phase 3.52 g/cm3
Solubility in water hydrolyzes
Other solvents chlorocarbons
Melting point 275 °C
Boiling point 346.7 °C
Structure
Coordination
geometry
octahedral
Crystal structure α:rhombohedral, β: hexagonal
Dipole moment 0 D
Hazards
MSDS External MSDS
Main hazards oxidizer
hydrolysis releases HCl
NFPA 704
R/S statement R: 34
S: 26-36/37/39-45
RTECS number YO7710000
Supplementary data page
Structure and
properties
n, εr, etc.
Thermodynamic
data
Phase behaviour
Solid
Spectral data UV, IR, NMR, MS
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

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).

Safety considerations

WCl6 is an aggressively corrosive oxidant and hydrolyzes to release hydrogen chloride.

References

  1. ^ 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.
  2. ^ 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.
  3. ^ M. A. Umbreit, K. B. Sharpless (1990). "Deoxygenation of Epoxides with Lower Valent Tungsten Halides: trans-Cyclododecene". Org. Synth.; Coll. Vol. 7: 121. 
 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Tungsten_hexachloride". A list of authors is available in Wikipedia.
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