Stability Constant of Rare Earth Metals with Substituted Thiazoles at 298.15K

Abstract

The stability constant on complexation of rare earth metal ions Eu (III), Gd (III), Nd (III) and Tb (III) with substituted thiazole in 70% Dioxane (Dx)-water mixture have been determined by a pH and spectrophotometric method at 298.15K and ionic strength 0.1mol.dm-3 (sodium perchlorate). At constant temperature, the stability constant of the formed complexes decreases in the order Tb (III), Gd (III), Eu (III), Nd (III). The dissociation process is non-spontaneous, endothermic and entrophically unfavorable while formation of metal complexes has been found to be spontaneous, endothermic and entrophically favorable.