The formation of mixed ligand complexes was studied in the Al(edta)-, Ga(edta)-, In(edta)- and Tl(edta)--halide and -sulphide ion systems by potentiometry, using glass and anion-selective electrodes. The stability constants (log KMLF) of the mixed ligand complexes M(edta)F2- were found to be 4.8±0.2, 1.9±0.1 and 0.9±0.1 for Al3+, Ga3+ and In3+, respectively. Values of log KMLX = 2.3±0.2, 3.5±0.15 and 5.9±0.2 were measured for Tl(edta)X2-, X = Cl-, Br- and I-, respectively. Complexes M(edta)S3- are described. The values of log KMLS were calculated to be 10.3, 10.6 and 9.4 for Al3+, Ga3+ and In3+, respectively. Ionic-covalent interactions in the mixed complexes are discussed. The stability constant of Tl(edta)- was reinvestigated via spectrophotometric study of the competition reaction in the Tl3+-H+-(edta)4--X- system.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Inorganic Chemistry
- Materials Chemistry