<Original Papers>Studies of Xanthate Complex by Solubility Method

Solubility product constants, K_ of M(EX)_2 in which EX^- means ethyl xanthate ion, C_2H_5OCS_2^-, were determined by taking the sub-reactions into consideration. In order to determine K_ of the complex, the method of solubilities in an excess of metal ions was examined. K_ for Pb(EX)_2,Cd(EX)_2,Cu(EX)_2,Ni(EX)_2 and Zn(EX)_2 were calculated to be 1.1×10^, 8.6×10^, 2×10^, 1.8×10^ and 3.5×10^ at 25℃ and at an ionic strength 1.0,respectively. Comparing the values of K_ with K_1 (the stability the constant of M (EX)^+ ion), it became evident that K_1 decreased with the increase of K_