Insertion of a Two-Dimensional Iron-Chloride Network between Perovskite Blocks. Synthesis and Characterization of the Layered Oxyhalide, (FeCl)LaNb2O7

• Published in: Chemistry of materials 2003-04, Vol.15 (7), p.1480-1485
• Main Authors: Viciu, Liliana, Koenig, Julien, Spinu, Leonard, Zhou, Weilie L, Wiley, John B
• Format: Article
• Language: English
• Subjects: Chemistry; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Inorganic chemistry and origins of life; Inorganic compounds; Magnetic phase boundaries (including magnetic transitions, metamagnetism, etc.); Magnetic properties and materials; Magnetically ordered materials: other intrinsic properties; Miscellaneous; Physics; Preparations and properties; Structure of solids and liquids; crystallography; Structure of specific crystalline solids
• ISSN: 0897-4756; 1520-5002
• DOI: 10.1021/cm0208253

A low-temperature (350 °C) ion-exchange reaction was used to insert Fe−Cl layers between the perovskite blocks of a double-layered Dion−Jacobson compound. The product, (FeCl)LaNb2O7, contains iron coordinated by two apical oxygens from the perovskite layer and four in-plane chlorines within the interlayer space. Rietveld structural analysis of X-ray powder diffraction data confirms the formation of the two-dimensional iron−chlorine networks with the iron cations moving slightly off the ideal octahedral coordination. Thermal analyses in oxygen, argon, and hydrogen showed this compound is metastable, decomposing exothermically between 600 and 750 °C. Magnetic measurements show Curie−Weiss behavior at higher temperatures consistent with Fe2+ in a high-spin d 6 configuration. At lower temperatures two transitions are observed:  below 80 K an antiferromagnetic transition occurs, and below 10 K spins realign in a ferromagnetic fashion.