[en] By the method of electromotive forces with liquid electrolyte thermodynamic properties of tellurium-saturated solid solutions of CdTe-HgTe system with cadmium telluride mole part from 0.06 to 1.0 have been investigated. Partial and integral values of the Gibbs energies, formation enthalpies and entropies of solid solutions (CdTe)_x(HgTe)_1-x are calculated and boundaries of their stability as to the temperature and composition are ascertained. Curves of binodal and spinodal decomposition are calculated and plotted; critical point has the coordinates X_CdTe=0.535, T=456.5 K