THE APPLICATION OF MERCURY HEMISPHERICAL ULTRAMICROELECTRODES TO THE STUDY OF VERY CONCENTRATED AMALGAMS - DIFFUSION-COEFFICIENTS OF THALLIUM

Mercury hemispherical ultramicroelectrodes were used, in chronoamperometric studies, for the determination of the diffusion coefficient of thallium in its concentrated amalgams up to 1.2 M. The determination was based (1) on the amalgam oxidation limiting current density vs. time dependence and (2) on electroreduction of thallium(I) from its 0.1 M solution at potentials corresponding to the foot of voltammetric curves. In both cases the dependences of In I(l) (I) vs. time were linear, with a slope dependent only on the diffusion coefficient and the square of the electrode radius. The diffusion coefficient values obtained are reliable.