The anion exchange of metal complexes-XII. The cadmium and mercury-halide systems

The distribution of trace cadium and mercury ions between Dowex-1 strong base anion exchanger, and solutions of hydrochloric acid, lithium chloride and bromide and sodium chloride, bromide and iodide has been measured. Resin ligand activity functions for these electrolyte-resin systems were obtained and used to show that the predominant complex species in both solution and resin, over the halide concentration range one M to saturation, is the tetrahalide. Only in hydrochloric acid (but not in hydrobromic acid) is there evidence for other species, which may be the undissociated acids, as suggested in the literature. The results for the other electrolytes indicate the validity of the effective ligand activity concept also in bromide and iodide solutions.