Phase Equilibrium in the CsCl + YbCl3 + HCl (∼11.3 %) + H2O System at 298.2 K and Thermodynamic Properties of New Solid Phase Compounds

• Published in: Journal of chemical and engineering data 2013-11, Vol.58 (11), p.3125-3129
• Main Authors: Qiao, Zhan-Ping, Xie, Hai-quan, Chen, Xin, Wang, Hui
• Format: Article
• Language: English
• ISSN: 0021-9568; 1520-5134
• DOI: 10.1021/je4005867

Solubility was studied in the CsCl + YbCl3 + HCl + H2O quaternary system along the (∼11.3 %) HCl section at 298.2 K using the isothermal solubility method, and the corresponding phase diagram was plotted. The compositions of solid phases were determined by the Schreinemaker’s wet residues technique. The system was complicated with four equilibrium solid phases CsCl, Cs4YbCl7·4H2O, Cs2YbCl5·5H2O, and YbCl3·6H2O. The compound Cs4YbCl7·4H2O was incongruently soluble, and the compound Cs2YbCl5·5H2O was congruently soluble in the system. The new solid phase compounds were characterized by chemical analysis, X-ray diffraction (XRD), and thermogravimetric/differential thermogravimetric (TG-DTG) techniques. The standard molar enthalpies of solution of Cs4YbCl7·4H2O and Cs2YbCl5·5H2O in water were measured to be (18.19 ± 0.47) and (13.22 ± 0.27) kJ·mol–1 by microcalorimetry under the condition of infinite dilution, and their standard molar enthalpies of formation were determined as being – (4039.2 ± 2.2) kJ·mol–1 and – (3469.2 ± 1.3) kJ·mol–1, respectively.