XAFS study of copper species stabilized in the interlayer space of layered perovskite oxides

New intercalation compounds with Cu²⁺ ions in the interlayer of layered perovskite oxides, OA_1-xCa_2-xLa_xNb₃O₁0 (OA = n-octylammonium ion, 0 ≤ x < 1), have been prepared by ion-exchange reaction, and characterized by means of XRD and XAS. For the detail elucidation of the fine structure of the Cu K-edge XANES spectra, polarized XAS was applied for the [Cu(en)₂]²⁺ and Cu²⁺ ions intercalated to the single crystal. According to the XANES and EXAFS spectra measured at Cu K-edge, copper ions are four-coordinated. In addition, XANES spectra have shown that the charge transfer from host layer to intercalated ions influences on the chemical state of copper ion.