IRON(III) COMPLEXES IN SOLUTIONS OF PROTONATED 5-SULFOSALICYLATE IONS

Complex formation of iron (III) with protonated 5-sulfosalicylate ions was studied over the pH range from 1 to 4 in 3 M NaClO4 solutions by a potentiometric method using the iron (III) - iron(II) redox system. It was seen by calculations accounting for the degree of protonation o f the sulfosalicylate ions and for the degree of hydrolysis of the iro n(III) ions that protonated iron(III) disulfosalicylate complexes FeH( SSal)22- and mixed hydroxy sulfosalicylate complexes Fe(OH)SSal- which had not been studied previously are formed in the solutions studied i n addition to the complexes FeSSal and Fe(SSal)23- described in the li terature. The equilibrium constants of the formation reactions of thes e complexes were calculated.