Entropy of solubility of substitutional impurities in solid compounds

Abstract

The vibrational solubility entropy, ΔSsol, is evaluated for vanishingly low solid solubilities in a very simplified calculation. Δ Ssol is thus simply related to the Einstein frequencies of the pure solids. In addition, when the impurity introduces charge compensating vacancies, ΔSsol includes the vacancy formation entropy, which becomes the predominating term. Results are in reasonable agreement with the few available experimental values.