Conductivity study of association of K2Mg[Fe(CN)6], K2Ca[Fe(CN)6] and K2Ba[Fe(CN)6] in aqueous solutions

The stability constants, Kp0, of ion pairs M2+.[Fe(CN)6]4- and their equivalent conductivities, λp0, at infinite dilution were evaluated by means of two-parameter fitting from the conductivities measured in very diluted aqueous solutions of double hexacyanoferrates of the type K2M(II).[Fe(CN)6] at 25 °C with the use of the limiting Debye-Huckel formula for ionic activity coefficients and Onsager limiting formula for the conductivity of strong electrolytes extended to electrolyte mixtures. Thus, Kp0 = 0.66, 0.72, and 0.76 . 104 dm3/mol and λp0 = 46, 49, and 53 S cm2 /val, respectively.