MECHANISM OF HYDROLYSIS OF AQUOMANGANESE(2) ION IN PERCHLORATE MEDIA

Following the observation[1, 2] by kinetic and pH-difference methods of changes in the aquoiron(II) ion at pH 3-4 involving proton transfer to solvent, and the observation by the pH- difference method of further changes in the aquoiron(II) ion at pH > 4 involving polymerization, the latter method has been applied to the aquomanganese(II) ion in perchlorate media. Proton transfer to solvent is found at pH ∼ 3.5, and at higher pH polymerization occurs. It is concluded, as found in the iron(II) case[2], that the polymer is mainly a dimer, hydrated Mn2+H2OMn2+. Thermodynamic data are calculated for the loss of the first proton from the monomeric aquomanganese(II) ion, and discussed in relation to similar data for other ions in the first transition series. © 1969.