HYDROLYSIS OF (CH3)HG- SALT EFFECTS AND COMPLEX-FORMATION( IN DIFFERENT IONIC MEDIA )

The hydrolysis of monomethylmercury(II) was studied potentiometrically , in NaNO3, Na2SO4, and NaCl aqueous solution, in a wide range of ioni c strengths (NaNO3, 0 less than or equal to I less than or equal to 3. 25; Na2SO4, 0 less than or equal to I less than or equal to 1; NaCl, 0 less than or equal to I less than or equal to 3 mol dm(-3)) and at t = 25 degrees C. For the reaction (CH3)Hg+ = (CH3)Hg(OH)(o) + H+, we fo und log K-1 = -4.528 (I = 0 mol dm(-3)). The species [(CH3)Hg](2)(OH)( +) was also found, with log beta(2) = -2.15. Monomethylmercury(II) for ms quite strong complexes with Cl- (log K = 5.45, I = 0 mol dm(-3)) an d SO42-(log K = 2.64, I = 0 mol dm(-3)). The dependence on ionic stren gth of formation constants was considered by using a Debye-Huckel type equation. Hydrolysis and complex formation constants (at different io nic strengths) obtained were used to calculate the interaction paramet ers of Fitter equations.