Novel protonated and hydrated image Ruddlesden–Popper phases, HxNa1−xLaTiO4·yH2O, formed by ion-exchange/intercalation reaction

New derivatives of layered perovskite compounds with H3O+ ions, H+ ions and water molecules in the interlayer, HxNa1−xLaTiO4·yH2O, were successfully synthesized by an ion-exchange/intercalation reaction with dilute HCl solution, using an image member of Ruddlesden–Popper phase, NaLaTiO4. Powder X-ray diffraction revealed that the layered structure changed from space group P4/nmm with image and image to I4/mmm with image and image after the ion-exchange/intercalation reaction at pH 5. The change of space group indicates that the perovskite layers are transformed from staggered to an eclipsed configuration through the ion-exchange/intercalation reaction. Thermogravimetric analysis and high-temperature powder X-ray diffraction suggested the existence of the secondary hydrated phase by dehydrating HxNa1−xLaTiO4·yH2O at 100 °C.