(Sb-Cl_ax). At low temperatures, converts to the dimer, dioctahedral , structurally related to niobium pentachloride.

Preparation

is prepared by the chlorination of . This reaction is used to produce around 10,000 tonnes of per year (as of 2000).
: (?H = -124 kJ/mol)

exists in equilibrium with and chlorine, and at 180 °C the degree of dissociation is about 40%. Because