Although SCl 4 is unstable, SeCl 4 and TeCl 4 are stable, probably as a result of the larger sizes of the
central atoms and the greater polarity of the bonds. In the gaseous state, SeCl 4 dissociates, but TeCl 4 is
stable up to approximately 500°C. When heated to melting, TeCl 4 becomes a good electrical conduc-tor, possibly because of the ionization reaction