KINETIC STUDIES ON 1-1 COMPLEX OF IRON(3) AND CHROMATE IONS IN PERCHLORIC ACID SOLUTION

Rate studies have been carried out on the complex formation reaction of Fe3+ and HCrO4-. The rate expression is d[Fe- CrO4+]/dt = Kf[Fe3+] [HCrO4-] [H+]-1 - Ka[FeCrO4+] with Kf = 35.0 ± 1.3 sec-1 and Ka = 15.1 ± 1.3 sec-1 at 25.0° and 1.00 M ionic strength (LiClO4). The stability quotient of FeCrO4+ obtained from the rate studies was confirmed by independent spectrophotometric measurements. The proposed mechanism involves substitution of HCrO4- on FeOH2+ in accord with other iron(III) substitution reactions. © 1969, American Chemical Society. All rights reserved.