A novel molecular entity vacancy model was proposed to describe thermodynamic properties in a multi-component solution system using its binary interaction parameters only. A derivation of the model for its general expression was shown in detail. Under some special conditions, this model could be reduced to Flory–Huggins equation, Wilson equation and non-random two liquids equation as well as molecular interaction volume model, respectively, and could be verified by Gibbs–Duhem equation, and could express thermodynamic properties of partially miscible systems. The predicted activities were in good agreement with experimental data of some liquid alloys. The results showed that the model was of better predictability and reliability because it has a certain physical basis.

Molecular Entity Vacancy Model. D.P.Tao: Fluid Phase Equilibria, 2006, 250[1-2], 83-92