The electrochemistry of indium was studied with voltammetry and chronoamperometry at glassy carbon, tungsten, and nickel electrodes in the basic and acidic aluminum chloride-1,2-dimethyl-3-propylimidazolium chloride molten salt at 27°C. In the basic melt, In(III) is complexed as [InCl5]2-, which could be reduced to indium metal through a three-electron reduction process. The electrodeposition of indium on glassy carbon and tungsten electrodes involves progressive three-dimensional nucleation on a finite number of active sites with diffusion-controlled growth of the nuclei. The electrodeposition of indium metal on a nickel electrode entails progressive three-dimensional nucleation on a large number of active sites. The formal potentials of the In(III)/In couple in the 44.4 to 55.6 and 49.0 to 51.0 mole percent (m/o) melts are -1.096 and -1.009 V, respectively, vs. Al(III)/Al in the 66.7 to 33.3 m/o.
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