AbstractEnergy‐dispersive x‐ray fluorescence (EDXRF) analysis of manganese compounds has been carried out. A significant dependence of the Mn Kα and Kβ x‐ray yields per incident photon and of the Kβ/Kα ratio on the valence state of manganese in these compounds was observed. The measurement of attenuation coefficients of these compounds, which are used in absorption corrections in XRF analysis, also showed similar effects. These results imply that the EDXRF elemental analysis results have inherent inaccuracies of the ord