Anodically generated mercury(II) ion as an indicator for metal–ligand formation equilibria

Abstract

In the presence of solute species which complex with Hg^II ions, the polarographic anodic dissolution wave for mercury is displaced towards more negative potentials relative to the value shown in non-complexing media. Competition for a ligand between anodically generated Hg^II ions and other metal ions added to a solution may be used to calculate formation equilibrium data for mononuclear complexes of the latter species. These principles have been exemplified by investigation of the interaction between the cadmium ion and the analytical masking agents thiourea and thiosulphate ion.