KLnTiO_4 (Ln = La, Nd, Sm, Eu, Gd, Dy): a new series of ruddlesden-popper phases synthesized by ion-exchange of HLnTiO_4

摘要

KLnTiO_4 (Ln = La, Nd, Sm, Eu, Gd, Dy), a new series of n = 1 Ruddlesden-Popper phases, was synthesized by a two-step ion-exchange reaction. HLnTiO_4 was first prepared by traditional acid exchange of NaLNTiO_4, and the KLnTiO_4 series was subsequently formed from the reaction of HLnTiO_4 with hot aqueous KOH. The ion exchange is stoichiometric, and the KLnTiO_4 phases are thermally stable to at least 700 deg C. All the KLnTiO_4 phases are orthorhombic and crystallize in space group Pbcm. The structures of KSmTiO_4, KGdTiO_4, and KDyTiO_4 were refined by the Rietveld method and found to be isostructural with their NaLnTiO_4 precursors. All the KLnTiO_4 phases from stable hydrates when exposed to a humidified atomosphere.