Activity coefficients of single complexes and coordination equilibria in three-component systems of the type MX2+ solvent + diluent. Systems involving CoCl2, ZnCl2, CuCl2, pyridine, benzene, chlorobenzene and o-dichlorobenzene
Abstract
Solubility isotherms for CoCl2, ZnCl2 and CuCl2 in mixtures of pyridine with benzene and o-dichlorobenzene, and the visible absorption spectra of the solutions containing CoCl2, have been determined. The results are analysed in terms of the nature of complexes existing in the liquid phases, their activity coefficients and the equilibrium constant of the reaction [CoCl2py4]⇌[CoCl2py2]+ 2py. Taking into account the regularities controlling the activity coefficients, the single complex existing in solutions of CuCl2 is shown to be pentacoordinate [CuCl2py3].