Collect. Czech. Chem. Commun. 1999, 64, 1262-1268

Solubility in the CuCl2-NaCl-H2O System and Hydration Analysis in the Case of Complexation

Jitka Eysseltováa,*, Vladimír Zbraneka and Jan Jirsákb

a Department of Inorganic Chemistry, Charles University, 128 40 Prague 2, Czech Republic
b V. B. Třebízský Secondary School, Smetana Sq. 1310, 274 01 Slaný, Czech Republic


The solubility diagram in the title system was studied at 25 °C. The results were compared with contradictional isotherms of other authors and one isotherm being in error was localized and rejected. The reliable solubility branches were treated with hydration analysis, which brings information on ionic processes in saturated solutions. Formation of coordination anions such as [CuCl3]- and [CuCl4]2- was found to be the main ionic process in saturated solutions in spite of the non-existence of the corresponding solid phase. The information obtained by this method for systems where hydration of components and complex formation take place simultaneously is demonstrated and discussed for the first time. A possibility of calculation of activity coefficients of the solute on both crystallization branches is discussed.

Keywords: Solubility; Hydration analysis; Activity coefficients; Crystallization; Copper(II) chloride.