Equilibrium Studies on Mixed Ligand Complexes of Some Tripositive Rare Earth Ions

Abstract

Interaction of the rare earth ions, La³⁺,  Ce³⁺,  Pr³⁺,  Nd³⁺,  Sm³⁺
and Eu³⁺ with the pair of ligands  1-amino-2-naphthol-4-sulphonic
acid (an, H₂A and o-aminophenol (ap, HB) have been studied in
aquous solution at 25°C (μ = 0.1 M KNO₃ /NaCI). Equilibrium
constants of the reactions involving the formations of the mixed
ligand species MAB,  MA₂B^2-,  MB₂A ^- (M = metal ion) and the
binary complexes containing up to three ligand molecules have been
evaluated from the pH-metric data, and coordinating behaviour of
the ligands in tire furruation of the mixed ligand complexes has
been discussed.