Entropies and Energies of Dimerization of Alkali Metal Halides

Abstract

Calculated entropies of dimerization for a number of gaseous alkali metal halides, assuming the rhombic planar model for the dimer, fall in the range —31.0±1.5 entropy units. Entropies of dimerization deduced from experimental data for several species diverge appreciably from the calculated values. The differences can be attributed to uncertainties in the graphical determination of dimerization energies. Energies of dimerization recalculated by combining experimental values of ΔF° (dimerization) with theoretical values of ΔS° (dimerization) correlate well with the interionic separations in the dimers.