Collect. Czech. Chem. Commun. 1985, 50, 1001-1009

Evaluation of phase diagrams of solvate-forming binary systems: The systems dimethyl sulphoxide-lithium nitrate and dimethyl sulphoxide-calcium nitrate

Ivan Horsák, Petr Pacák and Ivo Sláma

Institute of Inorganic Chemistry, Czechoslovak Academy of Sciences, 160 00 Prague 6


Phase diagrams of the solidus-liquidus type for two dimethylsulphoxide-nitrate systems have been evaluated using a rigorous method proposed previously. As both the systems involve the formation of solvates, the problem solved is one of simultaneous phase and chemical equilibria. The evaluation was performed by optimization of chosen adjustable parameters, namely the equilibrium constant of solvation, interaction parameters in expression for excess free energy, and the temperature and heat of fusion of pure crystalline solvate. In addition, a suitable model had to be found for the activities of ideal mixture components for the given type of system. The paper presents the first experimental data for the phase diagram of the system dimethyl sulphoxide-lithium nitrate