Growth and Structure of Rare-Earth Molybdate Crystals Na<sub>0.65</sub>La<sub>4.35</sub>Mo<sub>3</sub>O<sub>15.81±δ</sub>F<sub>0.07±ε</sub>
Nataliya E. Novikova,
Ekaterina I. Orlova,
Alexander M. Antipin,
Timofei A. Sorokin,
Vladimir B. Kvartalov,
Elena P. Kharitonova,
Nataliya I. Sorokina,
Olga A. Alekseeva,
Valentina I. Voronkova
Affiliations
Nataliya E. Novikova
Shubnikov Institute of Crystallography, Federal Scientific Research Centre “Crystallography and Photonics” of Russian Academy of Sciences, Leninskiy Prospekt 59, 119333 Moscow, Russia
Ekaterina I. Orlova
Shubnikov Institute of Crystallography, Federal Scientific Research Centre “Crystallography and Photonics” of Russian Academy of Sciences, Leninskiy Prospekt 59, 119333 Moscow, Russia
Alexander M. Antipin
Shubnikov Institute of Crystallography, Federal Scientific Research Centre “Crystallography and Photonics” of Russian Academy of Sciences, Leninskiy Prospekt 59, 119333 Moscow, Russia
Timofei A. Sorokin
Shubnikov Institute of Crystallography, Federal Scientific Research Centre “Crystallography and Photonics” of Russian Academy of Sciences, Leninskiy Prospekt 59, 119333 Moscow, Russia
Vladimir B. Kvartalov
Shubnikov Institute of Crystallography, Federal Scientific Research Centre “Crystallography and Photonics” of Russian Academy of Sciences, Leninskiy Prospekt 59, 119333 Moscow, Russia
Elena P. Kharitonova
Shubnikov Institute of Crystallography, Federal Scientific Research Centre “Crystallography and Photonics” of Russian Academy of Sciences, Leninskiy Prospekt 59, 119333 Moscow, Russia
Nataliya I. Sorokina
Shubnikov Institute of Crystallography, Federal Scientific Research Centre “Crystallography and Photonics” of Russian Academy of Sciences, Leninskiy Prospekt 59, 119333 Moscow, Russia
Olga A. Alekseeva
Shubnikov Institute of Crystallography, Federal Scientific Research Centre “Crystallography and Photonics” of Russian Academy of Sciences, Leninskiy Prospekt 59, 119333 Moscow, Russia
Valentina I. Voronkova
Faculty of Physics, Lomonosov Moscow State University, GSP-1, Leninskiye Gory, 119991 Moscow, Russia
Rare-earth sodium- and fluorine-substituted molybdates with the Na0.65La4.35Mo3O15.81±δF0.07±ε composition were synthesized for the first time as single crystals. An accurate X-ray diffraction analysis of three samples at room temperature showed that the obtained crystals are isostructural to undoped cubic compounds of the Ln5Mo3O16+δ family (space group Pn3¯n). Sodium cations partially occupy one of the two lanthanum positions and center the more distorted LaO8 polyhedra, while fluorine anions occupy over-stoichiometric oxygen positions in the vast interstices (cavities) of the structure. The partial substitution of fluorine atoms for oxygen ones affects the transport characteristics of compounds by activating the oxygen atoms in the anionic subsystem due to the effect of supplementary electrostatic repulsion between anions of different types.
