Tungsten(V) chloride explained

Tungsten(V) chloride is an inorganic compound with the formula W₂Cl₁₀. This compound is analogous in many ways to the more familiar molybdenum pentachloride.

Synthesis

The material is prepared by reduction of tungsten hexachloride. One method involves the use of tetrachloroethylene as the reductant^[1]

2 WCl₆ + C₂Cl₄ → W₂Cl₁₀ + C₂Cl₆The blue green solid is volatile under vacuum and slightly soluble in nonpolar solvents. The compound is oxophilic and is highly reactive toward Lewis bases.

When the same reduction is conducted in the presence of tetraphenylarsonium chloride, one obtains instead the hexachlorotungstate(V) salt:^[2]

Structure

The compound exists as a dimer, with a pair of octahedral tungsten(V) centres bridged by two chloride ligands. The W---W separation is 3.814 Å, which is non-bonding. The compound is isostructural with Nb₂Cl₁₀ and Mo₂Cl₁₀. The compound evaporates to give trigonal bipyramidal WCl₅ monomers.^[3]

Notes and References

1. Book: E. L.. McCann, III. T. M.. Brown. Tungsten(V) Chloride (Tungsten Pentachloride) . Inorganic Syntheses. XIII. 1972. 150–154. 10.1002/9780470132449.ch29. 978-0-470-13172-5 .
2. 10.1002/zaac.19834970221 . Über die Reaktion von 2,2-Dimethylpropylidinphosphan mit Wolframhexachlorid; die Kristallstrukturen von [(Cl₃PO)WCL₄(H₉C₄CCC₄H₉)] und [(H₅C₆)₄As][WCL₆] . 1983 . Uhl . G. . Hey . E. . Becker . G. . Weller . F. . Dehnicke . K. . Zeitschrift für anorganische und allgemeine Chemie . 497 . 2 . 213–223 .
3. F. A.. Cotton. F.A. Cotton. C. E.. Rice. Tungsten Pentachloride. Acta Crystallogr.. 1978. B34. 9. 2833–2834. 10.1107/S0567740878009322. 1978AcCrB..34.2833C .