Phase Diagrams and Physicochemical Properties for the Ternary System (CsCl + NaCl + H2O) at T = (298.15, 308.15, and 318.15) K

Complete phase diagrams and physico-chemical properties for the ternary system (CsCl + NaCl + H2O) were determined at T = (298.15, 308.15, and 318.15) K, respectively. The X-ray diffraction method and Schreinemaker’s wet residue method were used to verify the solid phase. The phase diagrams show this ternary system is a complex type. Three crystallization regions were found corresponding to the single salt NaCl, a compound CsCl·2NaCl·2H2O, and a solid solution series [Cs1–x(Na·H2O)x]Cl (x in [Cs1–x(Na·H2O)x]Cl changed from 0 to 0.43 (298.15 K), 0.39 (308.15 K), and 0.36 (318.15 K) at each temperature. With rising temperature, the crystallization area of NaCl increased, but CsCl·2NaCl·2H2O and [Cs1–x(Na·H2O)x]Cl decreased simultaneously. However, density and refractive index increased with increasing CsCl concentration.