Tungsten(III) chloride is the inorganic compound with the formula W6Cl18.

It is a brown solid, obtainable by chlorination of tungsten(II) chloride.

[2] Featuring twelve doubly bridging chloride ligands, the cluster adopts a structure related to the corresponding chlorides of niobium and tantalum.

In contrast, W6Cl12 features eight triply bridging chlorides.

A related mixed valence W(III)-W(IV) chloride is prepared by reduction of the hexachloride with bismuth:[3]