18WCl4 [W6Cl8]Cl4 + 12WCl5
or
3WCl4 WCl2 + 2WCl5[12]
The thermal decomposition of tungsten(IV) chloride to produce oktachloridotungsten(II) chloride and tungsten(V) chloride. This reaction takes place at a temperature of 450-500°C.