New rare-earth double-layered-perovskite oxyfluorides, RbLnTiNbO(6)F (Ln = La, Pr, Nd)

New Dion-Jacobson-type double-layered oxyfluoride perovskites, RbLnTiNbO(6)F (Ln = La, Pr, Nd), have been synthesized. Rietveld refinement of X-ray powder diffraction data (space group P4/mmm) shows the compounds to be isostructural with RbSrNb2O6F. Curie-Weiss behavior is observed in the Pr, Nd compounds. This series further illuminates the substitutional variations, both cationic and anionic, that can be achieved within the RbLaNb2O7 structure type. (C) 2002 Elsevier Science Ltd. All rights reserved.