A solution-solid equilibrium in ternary water-organic systems CuCl 2-L-H2O (L = dimethyl sulfoxide, N,N-dimethyl formamide, and acetonitrile) at 25°C was studied. The expansion of crystallization branches of individual solvates CuCl2•xL varies in parallel to the donor power of organic solvents. The existence of the mixed crystal-solvates CuCl2•2H2O•2(CH3)2SO, CuCl2•2H2O•2(CH3)2NCHO, CuCl2•H2O•(CH3)2NCHO, CuCl2•2H2O•CH3CN, and CuCl 2•3H2O•2CH3CN in the studied systems was proved. Various donor power of oxygen-containing solvents determines the composition of the first coordination sphere of the copper ion in the specified compounds: the coordination of the both solvents in the mixed crystal-solvates with DMF and the absence of water in the nearest environment of the copper(II) ions in the CuCl2•2H2O•2(CH3) 2SO compound.
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