Calculation of the Phase Diagram of the NaCl–RaCl2 System by Analyzing the NaCl–MCl2 Systems (M = Ca, Sr, Ba) Using the Schröder–Le Châtelier Equation

Abstract

Phase equilibria in the binary system NaCl-RaCl₂ were predicted based on the binary systems NaCl–MCl₂ (M = Ca, Sr, Ba). All the considered systems are of the eutectic type. Experimental data were processed, and functional dependences T_e/Z = f(Z) and T_e/r = f(r) were obtained, where T_e is the melting point of the eutectic in the binary systems NaCl–CaCl₂, NaCl–SrCl₂, and NaCl–BaCl₂; Z is the atomic number of Ca, Sr, or Ba; and r is its ionic radius. By further calculations using these functions, the melting point of the eutectic in the NaCl–RaCl₂ system was found. Using the Schröder–Le Châtelier equation, the composition of the binary eutectic in the predicted system and the molar enthalpy of melting of RaCl₂ were calculated, and branches of the liquidus of the system were constructed.