Chloride complexes of cobalt(II) in anion and cation exchangers

Abstract

Spectra of Co(II) ions entrapped in cation and anion exchangers containing Cl − have been examined to provide information regarding the nature of the complex ions in these media. Spectroscopic samples were cut from single beads of commercial quaternary amine or sulphonic acid exchangers. The internal Cl − concentration was varied at fixed Co(II) concentration by equilibration with gaseous HClH 2O mixtures. In both cation and anion exchangers the Co(II) co-ordination changes from octahedral to tetrahedral as the Cl − concentration increases. The spectrum of the tetrahedral species observed in anion exchanger is assigned to CoCl 4 2−. The spectra indicate that no inner sphere complexes are formed involving the fixed ionic groups of the exchangers.