COMPLEX-FORMATION EQUILIBRIA AT HIGH LIGAND CONCENTRATION - INDIUM(III)-CHLORIDE COMPLEXES

A potentiometric methodology has been used to study complex formation equilibria between Indium(III) and chloride at 25-degrees-C in solutio ns containing up to 5 molal chloride. During the experiments, both ion ic strength and free protons concentration were kept constant througho ut. indium amalgams have been employed to measure the activity of free Indium(III) with a junctionless cell; the analytical concentration of the metal has been varied by a coulometric methodology. Activity coef ficient variations, which take place during experiments, have been eva luated using the Specific Interaction Theory. Emf data are interpreted by assuming, in addition to the previously reported InCln3-n species with 1 less-than-or-equal-to n less-than-or-equal-to 4, also the prese nce of penta- and hexachloroindium(III) complexes.