Enthalpies of polymerisation of SbF5, NbF5 and TaF5

Abstract The enthalpies of polymerisation of SbF 5(g) , NbF 5(g) and TaF 5(g) have been estimated from molecular weight data to be −18.5, −25.9 and −25.7 kJ mol −1 respectively assuming mixtures of monomer and tetramer. Estimates of the entropy changes have also been made.