Speciation of the Chromium(III)-Salicylic Acid System Studied in 1.5 mol ·dm-3 KCl at 25 °C

Abstract

The complex species formed between chromium(III) and salicylic acid (H2sal) were studied in aqueous solution by means of electromotive force (emf(H)) measurements at 25 °C and in 1.5 mol ·dm-3 KCl as the ionic medium. The complexes were studied by the aging solution method, which consists of the preparation of different ligand/metal molar ratios at different pH values; the solutions were maintained at room temperature [(25 ( 1) °C] for 45 days; then potentiometric measurements were done, and the data were analyzed by means of the least-squares computational program LETAGROP, from which the respective stability constants and the stoichiometric coefficients of the complexes formed in aqueous solution were obtained. The results obtained indicate the formation of Cr(sal)+, Cr(sal)(OH), and Cr(sal)(OH)2 -.