SOLUTION STATE AND THERMODYNAMIC STUDIES ON BINARY COMPLEXES OF THE TH(IV) WITH SOME HYDROXY ACIDS

Abstract

A Solution state study on complexation behavior of Th(IV) with hydroxy acids (malic acid, lactic acid, salicylic acid and mandelic acid) has been carried out using the Irving–Rossotti titration technique in aqueous media and mixed media at different temperatures and ionic strengths. The dissociation constant and stability constants (logβ) of the resulting complexes have been calculated with the Fortran IV program BEST using the method of least squares and considering the BESTFIT model. Species distribution curves of complexes have been plotted as function of pH using the SPEPLOT Fortran IV program to visualize various species in equilibrium in the pH range 2–14. Thermodynamic properties were calculated and negative ∆G, ∆H and ∆S values indicated that complex formation is a spontaneous and exothermic process at these temperatures. To understand more about these equilibriums, the stability of these complexes was studied in presence of various systemic errors.