A comparative study of the polarographic behavior of cobalt(II), nickel(II), manganese(II), and zinc(II) in azide solutions

The electrochemical behavior of cobalt(II), nickel(II), manganese(II), and zinc(II) was studied by polarography at several azide concentrations. The reduction waves of cobalt(II) and nickel(II) exhibit a shift of the potential towards more positive values, with the increasing ligand concentration in solution. The maximum anticipation observed is 300 mV for cobalt(II) and 370 mV for nickel(II). In the case of zinc(II), an anticipation of only 27 mV is observed at low ligand concentrations, and for subsequent additions of ligand the reduction wave shifts towards more negative potentials. The behavior of manganese(II) is different, as the reduction wave only shifts towards more negative potentials.