Abstract
Stabilities of copper, palladium, nickel, cobalt, and iron chelates of various tyres of ligands involving the mercapto and the carbonyl group were compared each other by measuring the pH at 50% extractability of the chelates into chloroform and at incipient chelate formation. From the results of these experiments, relationship between chelating abilities and chemical structures of the ligands was confirmed. The ligands which involve conjugated double bond in their chelate ring and those involve thiolic acid ester group were found to have stronger chelating ability.
