Because the number of valence electrons affects the binding energy of core electrons in an atom , the rising edge energy is often used to experimentally detect oxidation state of metal atoms. For a limited set of compounds, this heuristic can work well: for example, the shift of the edge energy was successfully used as a fingerprint for oxidation state of Mn in silicate glasses . But other studies, such as those for chromium chloride compounds , demonstrate the difficulty of determining oxidation state of Cr from edge energy alone. The white line energy usually occurs shortly after the rising edge energy, and, surprisingly, the white line energy does not occur as one of the top 12 features for Bader charge in the current study. This suggests there is sufficient information in the rest of the spectrum to make accurate predictions, and also shows the limitation of relying on peak energies for determining metal oxidation states.