Mass spectrometry of the vapours over PbBr₂+MBr mixtures (M = Na, K, Rb, Cs)

Abstract

A mass spectrometric study of vapours above molten PbBr₂+MBr mixtures has revealed the existence of vapour species of general formula MPbBr₃ (M = Na, K, Rb, Cs). Second-law enthalpies of formation of these complexes were found to be in the range -39 to -44 kcal/mol; entropies of formation are estimated between -20 to -21 e.u. It is believed that these complex molecules have a bipyramidal structure.