STABILITY OF LEAD(II) COMPLEXES WITH 1,10-PHENANTHROLINE - POTENTIOMETRIC AND POLAROGRAPHIC STUDIES

Stability constants beta(1) and beta(2) of mono- and diphenanthroline complexes of lead(II) are calculated from a plot of equilibrium potent ial of lead amalgam versus 1,20-phenanthroline (phen) concentration in solutions containing lead(II) and 0.1 M NaNO3 (pH 6). The constants b eta(1) and beta(2), which are calculated from a plot of potential of r eversible cathodic wave of lead(II) complexe reduction versus phen con centration, are in good agreement with data obtained by the potentiome tric method. It is concluded that the phenanthroline complexes of lead (II) do not specifically adsorb at mercury electrode if free phen mole cules are present in large excess. The diffusion coefficients of lead( II) complexes with 1,10-phenanthroline are calculated.