Phase equilibrium systems of CsX + MnX2 + H2O (X = Cl, Br) at 298.15 K and standard molar enthalpy of formation of CsMnX3·2H2O and Cs2MnX4·2H2O

Abstract Two equilibrium diagrams of the ternary system (CsX + MnX2 + H2O, X = Cl, Br) at 298.15 K are reported in this paper. Each system has two double salts (CsMnX3·2H2O and Cs2MnX4·2H2O X = Cl, Br) in it and the elements of all double salts in phase diagrams are confirmed by Schreinemaker method. Equilibrium phase diagrams show that the chloride double salts are congruently soluble compounds in water, however that the bromide double salts are incongruently soluble compounds in water. All the double salts are characterized by titrimetric analysis, powder X-ray diffraction, thermogravimetric and differential thermalanalysis. The enthalpies of formation of these double salts are first calculated by measuring their enthalpies of dissolution.