Ionization equilibria of cobalt (II) chloride in dimethyl sulphoxide

Abstract Visible absorption spectra and the molar conductance curve for CoCl 2 in dimethyl sulphoxide (DMSO) have been determined and are analyzed in terms of the nature of ionization equilibria set up in the respective solutions. Auxiliary absorption spectra determinations of the CoCl 2 + Et 4 NCl and Co (ClO 4 ) 2 +Et 4 NCl mixed solutions indicate consecutive formation of the CoCl(DMSO) + 5 , CoCl 3 DMSO t- , and CoCl 2t- 4 complex ions, in addition to the Co(DMSO) 2+ 6 parent cation. Coordinative disproportionation producing the CoCl 3 DMSO t- complex anion is shown to predominate in the more concentrated solution of CoCl 2 in DMSO. Consecutive stability constants of the chloro-complexes of cobalt(II) are derived.