VANADIUM(III) COMPLEXES IN AQUEOUS SOLUTION WITH THE DICARBOXYLIC OXALIC, MALONIC AND SUCCINIC ACIDS

Abstract

The complex species formed in aqueous solution (25 °C, I = 3.0 mol.dm-3 KCl ionic medium) between V3+ cation and the dicarboxylic acids oxalic, malonic and succinic (H2L) have been studied potentiometrically. The application of the least-squares computer program LETAGROP to the experimental (emf H) data, taking into account the hydrolytic species of V3+ ion, indicates that under the experimental conditions employed the complexes [VHL]2+, [VL]+, [V(OH)L], [V(OH)2L]-, [VL2]-, [V(OH)L2]2-, [VL3]3- and [V(OH)L3]4- with oxalic acid, the complexes [VHL]2+, [VL]+, [VL2]-, [V(OH)L2]2-, [V(OH)2L2]3-, [VL3]3- and [V(OH)L3]4- with malonic acid, and the [VL]+ and [V(OH)L] complexes with succinic acid were formed. The stability constants of the complexes formed were determined