Host: The Ceramic Society of Japan
Effects of O2− or OH−-ion incorporation on the cage geometry in 12CaO7Al2O3 (C12A7) crystals are investigated by the Maximum Entropy Method (MEM)/Rietveld analyses of synchrotron powder X-ray diffraction data measured in SPring-8. The OH− ion is located at the cage center and symmetrically attracts two axially-coordinated Ca ions, while, the O2− ion is likely located at off-center positions and induces larger asymmetric Ca ion displacement.