Tungsten hexachloride

Tungsten hexachloride

α-Tungsten hexachloride
β-Tungsten hexachloride
Tungsten hexachloride 3D view
Names
IUPAC names Tungsten hexachloride Tungsten(VI) chloride
Identifiers
CAS Number	13283-01-7Y
3D model (JSmol)	Interactive image
ECHA InfoCard	100.032.980
EC Number	236-293-9
PubChemCID	83301
RTECS number	YO7710000
UNII	L32HZV95ZEY
CompTox Dashboard(EPA)	DTXSID40893933
InChI InChI=1S/6ClH.W/h6*1H;/q;;;;;;+6/p-6
SMILES Cl[W](Cl)(Cl)(Cl)(Cl)Cl
Properties
Chemical formula	WCl6
Molar mass	396.54g·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)
Solubility in water	Hydrolyzes
Solubilityin chlorocarbons	soluble
Magnetic susceptibility(χ)	−71.0·10−6cm3/mol
Structure
Crystal structure	α:rhombohedral, β: hexagonal
Coordination geometry	Octahedral
Dipole moment	0D
Hazards
Occupational safety and health(OHS/OSH):
Main hazards	oxidizer; hydrolysis releases HCl
Related compounds
Otheranions	Tungsten hexafluoride Tungsten hexabromide
Related compounds	Tungsten(IV) chloride Tungsten(V) chloride Molybdenum(V) chloride Chromyl chloride
Except where otherwise noted, data are given for materials in theirstandard state(at 25 °C [77 °F], 100 kPa). Yverify(what isYN?) Infobox references

Tungsten hexachlorideis aninorganic chemical compoundoftungstenandchlorinewith thechemical formulaWCl₆.This dark violet-blue compound exists asvolatilecrystals understandard conditions.It is an important starting reagent in the preparation of tungsten compounds.Other examples of charge-neutral hexachlorides arerhenium(VI) chlorideandmolybdenum(VI) chloride.The highly volatiletungsten hexafluorideis also known.

As ad⁰atom, tungsten hexachloride isdiamagnetic.

Preparation and structure

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

W + 3 Cl₂→ WCl₆

Tungsten hexachloride exists in both blue and redpolymorphs,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 atroom temperature.Although these polymorphs are distinctly colored, their molecular structures are very similar. Both polymorphs featureWCl₆molecules that haveoctahedral geometry,in which all six W–Cl bonds are equivalent, and their length is equal to 224–226pm.The densities are very similar: 3.68 g/cm³for α and 3.62 g/cm³for β. The low-temperature form is slightly more dense, as expected.

Reactions

Tungsten hexachloride is readilyhydrolyzed,even bymoistair,giving the orangeoxychloridesWOCl₄andWO₂Cl₂,and subsequently,tungsten trioxide.WCl₆is soluble incarbon disulfide,carbon tetrachloride,andphosphorus oxychloride.

Methylationwithtrimethylaluminiumaffordshexamethyl tungsten:

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

Treatment withbutyl lithiumaffords areagentthat is useful fordeoxygenationofepoxides.

ThechlorideligandsinWCl₆can be replaced by manyanionicligands including:bromide,thiocyanate,alkoxide,alkylandaryl).

ReductionofWCl₆can be effected with a mixture oftetrachloroethyleneandtetraphenylarsonium chloride:

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

The W(V) hexachloride is a derivative oftungsten(V) chloride.

It reacts witharsenicorhydrogen arsenideto formtungsten arsenide.

Safety considerations

WCl₆is an aggressivelycorrosiveoxidant,and hydrolyzes to releasehydrogen chloride.