Novel protonated and hydrated n=1 Ruddlesden-Popper phases, HxNa1-xLaTiO4 • yH2O, formed by ion-exchange/intercalation reaction

New derivatives of layered perovskite compounds with H3O+ ions, W ions and water molecules in the interlayer, HxNa1-xLaTiO4 (.) yH(2)O, were successfully synthesized by an ion-exchange/intercalation reaction with dilute HCl solution, using an n = 1 member of Ruddlesden-Popper phase, NaLaTiO4. Powder X-ray diffraction revealed that the layered structure changed from space group P4/nmm with a = 3.776(1) and c = 13.028(5) angstrom to I4/mmm with a = 3.7533(3) and c = 28.103(4) angstrom after the ionexchange/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 (.) yH(2)O at 100 degrees C. (c) 2005 Elsevier Inc. All rights reserved.