Complex formation equilibria of Felll with boric acid in presence of some aminopolycarboxylic acids

Department of Chemistry, University of Calcutta, University College of Science,

92, Acharya Prafulla Chandra Road, Kolkata-700 009, India

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Manuscript received 7 January 2003, accepted 14 October 2003

Equilibrium study on the mixed ligand complex formation of Fe^III with nitrilotriacetic acid and anthranilic acid diacetic acid (H₃L) in the absence and in the presence of boric acid in different molar ratios provide the evidence of formation of Fe(L) Fe(OH)^-, $Fe(L)(OH{)}_2^{2-}$, Fe(L)(H₂BO₄)^3- and Fe₂(L)₂(BO₄)^5- complexes in solution. Stability constants of the complexes and the complex formation equilibria in aqueous solution at 25 ± 1° at a fixed ionic strength, I= 0.1 M (NaNO₃) have been determined by potentiometric method.