ANION INDUCED ADSORPTION OF CADMIUM(2) ON MERCURY FROM IODIDE AND BROMIDE MEDIA

A detailed study of the adsorption of cadmium(ll) on mercury electrodes from iodide and bromide media is reported. The technique of double-potential step chronocoulometry was employed with a computer for both data acquisition and analysis. Significant adsorption of cadmium(H) from iodide and bromide media is demonstrated. The extent of adsorption correlates best with the amount of adsorbed halide rather than with the electrode potential or the electronic charge on the metal. On the basis of the very small changes in the charge on the electrode which are produced by the adsorption of cadmium(ll), and from the relationships between the amount of adsorption and the bulk halide ion concentrations, it is concluded that neutral cadmium(ll) species are adsorbed. Other instances of anion-induced adsorption of metal ions are examined in the light of the present results. © 1968, American Chemical Society. All rights reserved.