STUDIES ON THE KINETICS OF HYDROLYTIC EQUILIBRIA OF OXO-BROMOMOLYBDATES(V) AND THEIR COMPARATIVE-STUDIES WITH THE CORRESPONDING OXO-CHLORO SPECIES

Kinetics of the hydrolysis of MoOCl52-, MoOBr52- and MoOBr4- have been studied. Three different kinetic steps have been identified Probable mechanisms for all the processes have been suggested on the basis of t he observed kinetic parameters. The proposed scheme for the proces, Mo O3+ --> Mo2O34+ --> Mo2O42+ predicts the involvement of some transient intermediate species, The identical behaviour of MoOBr52- and MoOBr4- ions in aqueous solution has been observed, Activation parameters for chloro- and bromo-systems have been determined, A positive Delta S v alues for MoOCl52- and a negative value for the same for MoOBr52- and MoOBr4- are observed, indicating a dissociative mechanism for the chlo ro-system and an associative mechanism for the bromo-system for the pr ocess, Mo2O34+ --> Mo2O42+. The difference in the chloro- and bromo-sy stems has been explained. Dependence of halide ion and hydrogen ion co ncentration in the hydrolytic behaviour of oxohalomolybdates(v) has al so been explained.