Reliable method for determining the oxidation state in chromium oxides.

We show that an appropriate analysis of the electron energy loss spectra in relation to the Cr-O bonds gives a reliable methodology to obtain the oxidation state in chromium oxides. It is based on the energy difference between the Cr L(3) and O K edges, which acts as a measure of the binding energy difference between the Cr 2p(3/2) and O 1s core levels.