Voltammetric and chronoamperometric investigation of germanium amalgams: Part I. Properties of the homogenous amalgam

Abstract

Using cyclic voltammetry and chronoamperometry with several anodic steps the deposition and particularly the oxidation of germanium from a HMDE was investigated within pH range 4–12 at Ge (IV) concentrations ranging from 4×10 −7 M to 1×10 −4 M in the absence of ligands capable to form the complex compounds with Ge(IV) in a solution. It was found that the initially formed product of electrodeposition is a homogeneous, usually supersaturated amalgam. Germanium from this amalgam oxidizes at about 1 V (vs. mercury sulphate reference electrode) or after some induction period, the length of which depends on concentration of Ge(0) in mercury, it begins to crystallize forming heterogenous germanium amalgam. Germanium from this heterogenous amalgam oxidizes in a separate voltammetric peak at more positive potentials. The solubility of germanium in mercury was evaluated on the basis of the oxidation current of homogenous amalgam and the value obtained is equal to (2±0.5)×10 −7 M i.e. (1.1±0.3)×10 −7 wt. %. Applying the Stevens and Shain method the diffusion coefficient of germanium in mercury was found to be (1.32±0.1)×10 −5 cm 2 s −1.