Tungsten(IV) chloride

Tungsten(IV) chloride

Names
Other names tungsten tetrachloride
Identifiers
CAS Number	13470-13-8
ECHA InfoCard	100.157.353
CompTox Dashboard (EPA)	DTXSID30158866
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)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

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.

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:

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

Like most binary metal halides, WCl₄ is polymeric. It consists of a 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).