Neutron diffraction study on protonated and hydrated layered perovskite

A layered perovskite compound with Na+, D3O+ ions (H3O+) and D2O molecules (H2O) in the interlayer, D0.34Na0.66LaTiO4·0.59D2O, has been prepared by an ion-exchange/intercalation reaction with dilute DCl solution, using an n=1 Ruddlesden-Popper phase, NaLaTiO4. Its structure has been analyzed in order to clarify the interlayer structure by Rietveld method, using powder neutron diffraction data. The structure analysis revealed that the layered structure changed from the space group P4/nmm to I4/mmm after the ion-exchange/intercalation reaction, and it induced the transformation of perovskite layers from staggered to eclipsed configuration. The D2O molecules and D3O+ ions loaded in the interlayer statistically occupied the sites around a body-center position of rectangular space surrounded by eight apical O atoms of TiO6 octahedra in upper and lower layers.