Tungsten(III) chloride is the inorganic compound with the formula W<sub>6</sub>Cl<sub>18</sub>. It is a cluster compound. It is a brown solid, obtainable by chlorination of tungsten(II) chloride. Featuring twelve doubly bridging chloride ligands, the cluster adopts a structure related to the corresponding chlorides of niobium and tantalum. In contrast, W<sub>6</sub>Cl<sub>12</sub> features eight triply bridging chlorides.
A related mixed valence W(III)-W(IV) chloride is prepared by reduction of the hexachloride with bismuth: