Molten salts and their vapours : a thermodynamic and mass spectrometric study.

Transpiration vapour pressure and mass spectrometric studies indicate the existence of molecules AMC13' where A is Na, K, Rb or Cs, and M is Cd or Pb. The stability of these molecules, as indicated by their thermodynamic properties, is comparable with that of the alkali halide dimers. The thermodynamic properties of the melts in equilibrium with these species are interpreted in terms of complex ion formation. Electron impact studies and molecular orbital calculations of an extended H‚àö¬¿ckel type, are used to indicate a likely structure for AMC1 as well as for some ions and radicals. Using derived ionization potential and electron affinity data, a theory for the formation of complex molecules, and ions, is proposed. Finally, a comparison of the properties of the liquid and vapour states is made.