Mixed-metal hydroxycarboxylic acid complexes. Formation constants of complexes of U^VI with Fe^III, Al^III, In^III and Cu^II

Formation constants for mixed-metal complexes, K_mmc, between uranium (VI), as the central metal ion, and each one of the metal ions iron(III), aluminium (III), indium(III) and copper(II) have been determined using data from potentiometric measurements. In each case one of the hydroxy-carboxylic acids, citric, tartaric or malic, was used as a ligand. At 298.15 K the values of -log K_mmc for the investigated systems are uranyl iron (II) citrate, 2.45; uranyl iron(III) malate, 7.37; uranyl aluminium(III) citrate, 8.21; aluminium(III) tartarate, > 12; uranyl aluminium (III) malate, 8.06; uranyl indium (III) citrate, 11.3; uranyl indium (III) tartarate, 7.88; uranyl indium(III) malate, 7.45; uranyl copper(II) citrate -1.41; uranyl copper (II) tartarate, -1.17; and uranyl copper(II) malate, -1.11.