The thermodynamics of the formation of complexes between diethylenetriaminepenta-acetic acid and the lanthanide ions

Abstract

The changes in enthalpy accompanying the formation of complexes between diethylenetriaminepenta-acetic acid and the lanthanide ions, in aqueous solution at 27° and an ionic strength of 0·1M, have been measured using an isothermal fusion calorimeter. The enthalpies of complexing have been combined with the appropriate free energy changes to give the entropy changes. The factors which influence the stability of these complexes have been discussed.