The Solubility of Dithionates of Metal(11) Amine Complexes in Aqueous Sodium Chloride Solutions

The solubility of dithionates of metal (II) amine complexes ([MII(amine)n]S2O6: M=Ni, Cu, Zn, Cd; amine=en, pn, dien; n=2, 3) in aqueous sodium chloride. solutions (0∼1.552 mol/kg-H2O) was measured at the temperature range of 0.4∼70°C. The complexes [MII(amine), n]S2O6 were slightly soluble in aqueous solution. The sokbility of these complexes increased to some extent with the increase of solution temperature and concentration of coexisting sodium chloride, and with decreasing pH values. The solubility of the complex salt [ZnII(en)3]S2O6, however, gave only a minimum value at pH 10.3. The parameters of Asp, a, b, c and d in the equations ( 1 ) and ( 2 ) were determined for the individual complex salt log Ksp=log Kspo+8S[radical]I/(1+Asp[radical]I) (1)log Kspo=a+b log T+c/T+dT(2)