The formation constants (logKMALMA) of the complexes of the type (UO2.A.L] (whereA = IMDA, NTA or EDTA;L = catechol, resorcinol, phloroglucinol, pyrogallol, β-resorcylic acid or protocatechuic acid) have been determined potentiometrically at 25°C and ionic strength,I = 0·2 (mol dm−3, NaClO4) using the Irving-Rossotti approach. The formation constants of the binary complexes (logKKMAKM) have been found to lie in the sequence IMDA < NTA < EDTA, whereas those for the mixed ligand complexes (logKMALMA) follow the reverse sequence, IMDA > NTA > EDTA. due to the electrostatic effect.
