Mn Kβ X‐ray fluorescence line splitting arising from 3p 5 –3d n exchange interactions, is highly sensitive to the number of unpaired 3d electrons, serving as a powerful probe for manganese oxidation states. Because these spectral components are separated by only 11–12 eV, they are typically unresolved by standard laboratory spectrometers, necessitating synchrotron‐based high‐resolution X‐ray emission spectrometers. These techniques provide the required electronic‐structure sensitivity. However, their dependence on synchrotron facilities limits accessibility. This article presents an optimized laboratory‐based Wavelenth Dispersive X‐ray Fluorescence protocol that achieves high‐resolution spectra without hardware modification. By utilizing higher‐order diffraction, the method successfully resolves subtle variations in the Mn Kβ main line multiplet. The extent of splitting is quantified using the integrated absolute difference metric referenced to spin‐zero KMnO 4 . This approach yields a strong linear correlation ( R 2 = 0.9947) with unpaired 3d electrons, enabling the direct determination of the average oxidation state (AOS). By combining spectroscopic AOS with Mn (IV) values in a linear mixing model, the protocol resolves Mn(II) and Mn(III) fractions with < 4% relative error. This accessible methodology provides a practical, accurate alternative to synchrotron facilities for quantitative manganese speciation in complex geological materials.
Ashok Kumar Maurya (Tue,) studied this question.