This work is the analysis of phase equilibria using the thermodynamic model of solutions, in which it is assumed that the strong interaction between the liquid phase components is due to the presence of atomic complexes of different compositions (polyassociative solutions model-PAS model). It is an analysis of its effectiveness and validity when creating p-T-x phase diagrams for A(2)B(6) semiconductor compounds, as well as for magnetic oxide solid solutions crystallizing to a spinel structure. The theoretical analysis results were compared with the experimental ones. Conclusions were drawn regarding the effectiveness of the PAS model, application restrictions were discussed, and long-term perspective application directions in the analysis of phase equilibrium were identified. (C) 2012 Elsevier B.V. All rights reserved.