Tungsten hexachloride

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Tungsten hexachloride

α-Tungsten hexachloride

β-Tungsten hexachloride
Tungsten hexachloride
Tungsten hexachloride
3D view
3D view
Names
IUPAC names
Tungsten hexachloride
Tungsten(VI) chloride
Identifiers
3D model (
JSmol
)
ECHA InfoCard
 100.032.980 Edit this at Wikidata
EC Number
  • 236-293-9
RTECS number
  • YO7710000
UNII
  • InChI=1S/6ClH.W/h6*1H;/q;;;;;;+6/p-6
  • Cl[W](Cl)(Cl)(Cl)(Cl)Cl
Properties
WCl6
Molar mass 396.54 g·mol−1
Appearance dark blue crystals, moisture sensitive
Density 3.52 g/cm3
Melting point 275 °C (527 °F; 548 K)
Boiling point 346.7 °C (656.1 °F; 619.8 K)
Hydrolyzes
Solubility in chlorocarbons soluble
−71.0·10−6 cm3/mol
Structure
α:rhombohedral, β: hexagonal
Octahedral
0 D
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
 oxidizer; hydrolysis releases HCl
Related compounds
Other anions
Related compounds
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Tungsten hexachloride is an

standard conditions. It is an important starting reagent in the preparation of tungsten compounds.[1] Other examples of charge-neutral hexachlorides are rhenium(VI) chloride and molybdenum(VI) chloride. The highly volatile tungsten hexafluoride
is also known.

As a

diamagnetic
.

Preparation and structure

Tungsten hexachloride can be prepared by chlorinating tungsten metal in a sealed tube at 600 °C:[2]

W + 3 Cl2 → WCl6

Tungsten hexachloride exists in both blue and red

polymorphs, referred to respectively as α and β. The wine-red β can be obtained by rapid cooling whereas the blue α form is more stable at room temperature. Although these polymorphs are distinctly colored, their molecular structures are very similar. Both polymorphs feature WCl6 molecules that have octahedral, in which all six W–Cl bonds are equivalent, and their length is equal to 224–226 pm. The densities are very similar: 3.68 g/cm3 for α and 3.62 g/cm3 for β. The low temperature form is slightly more dense, as expected.[3]

Reactions

Tungsten hexachloride is readily

phosphorus oxychloride.[2]

hexamethyl tungsten
:

WCl6 + 3 Al2(CH3)6 → W(CH3)6 + 3 Al2(CH3)4Cl2

Treatment with

butyl lithium affords a reagent that is useful for deoxygenation of epoxides.[4]

The

aryl
).

Reduction of WCl6 can be effected with a mixture of tetrachloroethylene and tetraphenylarsonium chloride:[5]

2 WCl6 + Cl2C=CCl2 + 2 (C6H5)4AsCl → 2 (C6H5)4As[WCl6] + Cl3C−CCl3

The W(V) hexachloride is a derivative of tungsten(V) chloride.

It reacts with

hydrogen arsenide to form tungsten arsenide.[6][7]

Safety considerations

WCl6 is an aggressively

oxidant, and hydrolyzes to release hydrogen chloride
.

References

  1. ISBN 978-0-471-93623-7
    ..
  2. ^
    ISBN 978-0-470-13162-6
    .
  3. doi:10.1107/S0567740874004572
    ..
  4. ^ M. A. Umbreit, K. B. Sharpless (1990). "Deoxygenation of Epoxides with Lower Valent Tungsten Halides: trans-Cyclododecene". Organic Syntheses; Collected Volumes, vol. 7, p. 121.
  5. doi:10.1002/zaac.19834970221
    .
  6. ISBN 978-1-4615-4907-9
    .
  7. ISBN 978-3-662-13401-6
    .
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