汞(II)-甲基百里酚兰-X(SCN^-,Br^-,I^-)三元混合配位化合物稳定常数的测定

The determination of stability constants of ternary mixed ligand complexes of mercury (II)-methyl thymol blue-X(SCN, Br, I)

With mercury (II)-methyl thymol blue-X (SCN, Br, I) as example, two methods are investigated in this paper. The first one bases on the variation experimental design, so that classical method of degree of dissociation can be used to calculate the stability constant from the molar ratio curve obtained. This method is simple, adaptable to cases where the decomposition is relatively weak. The second method requires the preliminary acquisition of the equilibrium constant of the decomposition reaction, with the calculation of the stability constant of the preceding formation reaction thereon. The evaluation procedure is more strict. Thhis method is applicable whether the decomposition reaction is strong or weak. Thus, we obtain stability constants of ternary complexes with rather strong subsequent decomposition reaction, such as Hg.MTB.I. Results obtained are rather satisfactory.