The determination of the valency of manganese in mineralogical and environmental samples by X-ray emission spectroscopy

Abstract: The K3 X-ray emission spectrum arising from 3p---, ls transitions in transition metal ions can be complicated by interaction between unpaired 3d electrons and the odd 3p electron in the final state. A non-diagram line, K/3 ' appears at lower emission energy than the diagram line Kill,3. For lighter transition metals the intensity ratio of K/ ~ r to Kill,3 decreases with the number of unpaired 3d electrons. This enables this intensity ratio to be used to determine oxidation state. This effect is demonstrated for the simple oxides MnO, Mn203 and MnO2, and for the anion MnO 4. Distinct spectra re obtained that can be related to the oxidation state of the manganese. The valency of manganese is then determined in mineral samples and in sand grains coated with manganese encrustations from water purification plants. X-ray emission spectroscopy is widely used for the elemental analysis of mineral and environ-mental samples. Less widely appreciated is the fact that an emission line is not only indicative of an element's presence, but can exhibit structur