Pulse radiolysis study of monovalent cadmium, cobalt, nickel and zinc in aqueous solution. Part 1.—Formation and decay of the monovalent ions

Abstract

The spectra and extinction coefficients of the hyper-reduced metal ions Cd⁺, Co⁺, Ni⁺ and Zn⁺ produced in the pulse radiolysis of aqueous solutions of the corresponding divalent ions (M²⁺) have been measured, and the reactions of these species have been investigated in the absence of oxidising solutes. In the absence of OH scavengers M⁺(except Ni⁺) decays by second order kinetics at approximately the diffusion controlled rate, and the decay is attributed to reoxidation of M⁺ by OH. Evidence for the oxidation of Co²⁺ by OH is presented. In the presence of formate ion, methanol, isopropanol or t-butanol as OH scavengers the decay of M⁺ is slower, varies with the scavenger used and is only approximately second order. Spectra of long lived products are presented. It is suggested that M⁺ can react with itself and with the radical formed from the organic solute.