Abstract
Solution equilibria of the system zinc(II)—nitrilotriacetic acid (NTA)—secondary ligand (L) have been studied. The secondary ligands investigated are thiol amino-acids and related molecules. Potentiometric titrations of reaction mixtures containing equimolar Zn
2+, NTA and secondary ligand have shown the formation of 1 : 1 : 1 ternary complexes. The formation constants of these complexes have been determined at 25° (μ = 0.1
M, KNO
3). The mode of chelation is discussed.