Pitzer Model Based Study of CsX-NiX2-H2O (X = Cl, Br) Systems at 298.15 K

Abstract

The Pitzer ion-interaction model was used for simulating the CsX-NiX2-H2O (X = Cl, Br) systems at 298.15 K. The necessary thermodynamic functions (binary and ternary parameters, thermodynamic solubility products) were calculated and the theoretical solubility diagrams plotted. A very good agreement was found between the calculated and observed data.

Thermodynamics of formation of double salts and mixed crystals from aqueous solutions

“…For most of the systems investigated, the model predicted solubilities in ternary mixtures agree very well with the experimental data obtained by us [27][28][29]33,[36][37][38]54,58,61,62] and those given in the literature . Additional experiments were performed [27][28][29]31,41,44] to check contradictory data reported in the literature and specify the type of the solubility diagrams.…”

Study of (m1LiX+m2CaX2)(aq) wheremidenotes molality andXdenotes Cl, or Br at the temperature 298.15 K

“…(5,(17)(18)(19) In calculating the ternary parameters we have included the unsymmetrical mixing terms E θ and E θ , according to reference 14. In our previous studies on chloride and bromide systems (5,6,15,(24)(25)(26)(27) containing the same cations (M + and Me 2+ ), and where double salts with the same stoichiometric composition crystallize, the following relationships have been found: the absolute value of the sum of the ternary parameters for the bromide systems is larger than that for the corresponding chloride system, and the r G o m values for the chloride double salts are lower than those for the corresponding bromide double salts. Using the foregoing model The solubility isotherms of the ternary solutions at T = 298.15 K are calculated on the basis of the thermodynamic functions obtained.…”

Thermodynamics of formation of double salts M2SO4·M′SO4·6H2O and M2SeO4·M′SeO4·6H2O where M denotes Rb, or Cs and M′ denote Co, Ni, or Zn

“…Then, the ternary parameters can be chosen by minimizing the difference between the experimentally determined and calculated solubility of the double salt in water. The applicability of this method has been demonstrated for systems in which double salts with different stoichiometric composition crystallize [28,32,33,35] [29][30][31][32], the common chloride-, and bromide-ion ternary systems with participation of the same univalent (Rb þ and Cs þ ) and bivalent (Co 2þ , Ni 2þ , and Zn 2þ ) cations have been simulated and the theoretical solubility isotherm was plotted. In the model for (m 1 RbCl + m 2 CoCl 2 )(aq) [32], the binary mixing parameter h(Rb,Co) was set equal to zero.…”

“…It has been demonstrated in previous studies that the Pitzer equations gave sufficiently precise description of the properties of binary [1,2,6,7,[18][19][20][21][22][23][24] and multicomponent [25][26][27][28][29][30][31][32][33][34][35][36][37] solutions.…”