For Co, interesting differences are indicated as a tendency as compared to the Ni cation. On charging, the behavior of Co is in line with the behavior of Ni, the edges shift to higher energies in agreement with the oxidation of the Co cation (see Figure However, on discharging by 60 mAh g -1 , only the equatorial site expands to a bond distance close to what has been observed for the original sample, and the apical bond distances remains high at around 260 pm. The edge position becomes similar to before charging but indicates a slightly higher oxidation state than in the original sample. We hypothesize that this could be interpreted by the formation of Co 3+ in an intermediate eg 4 b2g 1 a1g 1 (for d-orbital splitting in D4h symmetry) spin state, which can be well stabilized in a more square-planarrelated coordination. The large distance of the apical site indicates that the coordination around the Co-cation is more similar to a T' RP-type structure as observed for Nd2CuO4 with oxide ions occupying the equatorial and interstitial anion sites. On discharging the sample further to 180 mAh g -1 , the edge of Co shifts to a value which is 1.2 eV lower than the sample before charging. This change of oxidation state is additionally accompanied by an increase of the equatorial anion distance to 196 pm (again in conceptual agreement with increased lattice parameters a/b derived from diffraction analysis) and the apical bond distance reduces to 230 pm length. This indicates that oxidation states around or even lower than +2 might be possible on electrochemical reduction, which has been observed by chemical reduction of perovskiterelated cobaltates before .