DETERMINATION OF ENTROPY AND ENTHALPY VALUES OF METAL GALLIC ACID COMPLEXES AND THEIR COMPARISON WITH IRON GALLATE

The entropy and enthalpy values ed complex formation between 3,4,5 tri hydroxybenzoic acid and Cu(II), Cr(II), Mn(II), Mg(II) and Ca(II) were determined and compared with the iron gallic acid complexes, they wer e found to be comparable. It was also found that they show very large entropy values. When those values were compared with other complexes o f the same nature from literature, following points were noteworthy. 1 . Monodentate ligands do not show any drastic entropy change with triv alent metals as compared to divalent metals. 2. Polydentate ligands sh ow very high entropy values with tripositive metal as compared to dipo sitive metals. 3. Non transition metals show low entropy values with c helating agents as compared to transition metals.