Etude de Mn(II) en solution aqueuse perchlorique par résonance paramagnétique électronique

The behaviour of manganese(II) perchlorate in aqueous perchloric acid solution was studied by epr at 25 and 55 °C. The broadening of the band following addition of HClO4 considerably exceeds that normally caused by the increase in the viscosity. This result is interpreted in terms of the formation of an internal monoperchlorato complex in equilibrium with the external complex. The decrease in the relative intensity of the signal following addition of HClO4 confirms the presence of an internal monoperchlorato complex and permits the evaluation of its stability constant, (8.0 ± 1.5) × 10−2. The relative stability of the Mn(II) monoperchlorato complex compared to those of Co(II) and Ni(II) is explained by a consideration of the ligand field stabilization energy. [Journal translation]