Potentiometric and Spectroscopic Studies with Chromium(III) Complexes of Hydroxysalicylic Acid Derivatives in Aqueous Solution

The stoichiometries and stability constants of the chromium(III) complexes of hydroxysalicylic acid ligands (2,x-dihydroxy benzoic acids; 2,x-DHBA, x = 4-6)(H3L) were determined in aqueous solution by potentiometry and spectroscopy at 25 C and at an ionic strength of 0.1 mol L − (KNO3). The existence of Cr(HL)+ type complex was veried. The stability constants of coordination species that exist in Cr(III):2,x-DHBA systems were dened. In the acidic medium the major coordination species involve salicylate type coordination. The formation of monohydroxo complexes was observed at higher pH values. Key Words: Potentiometry, equilibria, chromium, stability constants, hydroxo complex