Diffusion coefficients and complex equilibria in solution—IV: Experimental determination and manipulation of diffusion data

An experimental method for effectively measuring the change of diffusion current of a metal ion in the presence of increasing concentration of a complexing ligand is described and applied to five metal-ligand systems. The method has been applied to cases of reversible and irreversible electrochemical behaviour and is shown to provide reliable formation-curve data. The systems selected have formation constants which range over some ten orders of magnitude and in most cases the values obtained agree satisfactorily with those reported in the literature. In one case equilibrium data have been calculated for the first time.