Effect of Cl— and SO42— on the Paramagnetic Resonance Linewidth of Mn2+ in Aqueous Solution and the Rates of Formation of the Complex Ions

Abstract

The linewidth of one of the hyperfine components in solutions of Mn(ClO₄)₂ containing added NaCl and Na₂SO₄ was studied from 20°—200°C at 9000 Mc/sec. The chloride ion contributes little broadening at 0.1M below 80°C but considerable broadening is obtained above this temperature. The sulfate contributes broadening at all temperatures. The rates of formation of ``inner‐sphere'' and ``outer‐sphere'' complexes are discussed together with their rates of relaxation. At the lower temperatures the ``outer‐sphere'' complexes primarily contribute to the broadening while at the higher temperatures the ``inner‐sphere'' complexes also contribute. From the broadening above 80°C the rate of formation of the ``inner‐sphere'' complexes are evaluated.