Tungsten(IV) chloride

Tungsten(IV) chloride is an inorganic compound with the formula WCl₄. It is a diamagnetic black solid. The compound is of interest in research as one of a handful of binary tungsten chlorides.

Tungsten(IV) chloride

Names
Other names tungsten tetrachloride
Identifiers
CAS Number	13470-13-8
3D model (JSmol)	Interactive image
ChemSpider	122991
ECHA InfoCard	100.157.353
EC Number	629-145-3
PubChem CID	139468
CompTox Dashboard (EPA)	DTXSID30158866
InChI Key: YOUIDGQAIILFBW-UHFFFAOYSA-J InChI=1S/4ClH.W/h4*1H;/q;;;;+4/p-4
SMILES Cl[W](Cl)(Cl)Cl
Properties
Chemical formula	Cl4W
Molar mass	325.65 g·mol−1
Appearance	black solid
Density	4.62 g·cm−3
Melting point	450 °C (842 °F; 723 K)
Hazards
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H302, H314
Precautionary statements	P260, P264, P270, P280, P301+P312, P301+P330+P331, P303+P361+P353, P304+P340, P305+P351+P338, P310, P321, P330, P363, P405, P501
Related compounds
Other anions	Tungsten(IV) fluoride
Related compounds	Tungsten(V) chloride Tungsten hexachloride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Structure and preparation

WCl₄ is usually prepared by reduction tungsten hexachloride. Many reductants have been reported, including red phosphorus, tungsten hexacarbonyl, gallium, tin, and antimony. The latter is reported to be optimal:^[1]

${\displaystyle \mathrm {3\ WCl_{6}+2\ Sb\longrightarrow 3\ WCl_{4}+2\ SbCl_{3}} }$

Like most binary metal halides, WCl₄ is polymeric. It consists of linear chains of tungsten atoms each in octahedral geometry. Of six chloride ligands attached to each W center, four are bridging ligands. The W-W separations are alternatingly bonding (2.688 Å) and nonbonding (3.787 Å).

Reactions

Reduction of tungsten(IV) chloride with sodium yields the ditungsten(III) heptachloride derivative:^[2]

2 WCl₄ + 5 thf + 2 Na → [Na(thf)₃][W₂Cl₇(thf)₂] + NaCl