Conductance Behavior of Some Hexa-amminecobalt(III) Complexes and Their Ion Association in Aqueous Solutions

Abstract

Abstract The conductance behavior of some hexa-amminecobalt(III) complexes in dilute aqueous solutions at 25°C was studied in association with the ion-pair formation of hexa-amminecobalt(III) ions. The equivalent conductivities were analyzed according to the Onsager theory, and the thermodynamic formation constants, K, of the ion-pairs, [Co(NH3)6]3+·Aza−, were determined. The logK values obtained are 1.40 (perchlorate), 1.63 (nitrate), 1.65 (bromide), 1.38 (iodide), and 3.25 (oxalate). These values were compared with the formation constants calculated from the spectroscopic data, and discussed in terms of Bjerrum’s theory on ion association.