Alignment of acentric MoO3F33- anions in a polar material: (Ag3MoO3F3)(Ag 3MoO4)Cl

Paul A. Maggard, Tiffany S. Nault, Charlotte L. Stern, Kenneth R. Poeppelmeier

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Abstract

(Ag3MoO3F3)(Ag3MoO 4)Cl was synthesized by hydro(solvato)thermal methods and characterized by single-crystal X-ray diffraction (P3m1, No. 156, Z=1, a=7.4488(6)Å, c=5.9190(7)Å). The transparent colorless crystals are comprised of chains of distorted fac-MoO3F33- octahedra and MoO42- tetrahedra anions, as suggested by the formulas Ag3MoO3F3 and Ag 3MoO4+, and are connected through Ag + cations in a polar alignment along the c-axis. One Cl- anion per formula unit serves as a charge balance and connects the two types of chains in a staggered fashion, offset by ∼1/2×c. In MoO 42-, the Mo atom displaces towards a single oxide vertex, and in MoO3F33-, the Mo displaces towards the three oxide ligands. The ordered oxide-fluoride ligands on the MoO 3F33- anion is important to prevent local inversion centers, while the polar organization is directed by the Cl - anion and interchain dipole-dipole interactions. The dipole moments of MoO3F33- and MoO4 2- align in the negative c-axis direction, to give a polar structure with no cancellation of the individual moments. The direction and magnitude of the dipole moments for MoO3F33- and MoO 42- were calculated from bond valence analyses and are 6. 1 and 1.9debye (10-18esucm) respectively, compared to 4.4debye for polar NbO6 octahedra in LiNbO3, and 4.5debye for polar TiO6 octahedra in KTiOPO4 (KTP).

Original languageEnglish
Pages (from-to)27-33
Number of pages7
JournalJournal of Solid State Chemistry
Volume175
Issue number1
DOIs
Publication statusPublished - Oct 2003

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Keywords

  • Dipole moment calculation
  • Metal oxyfluoride anions
  • Polar compound

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry
  • Inorganic Chemistry
  • Materials Chemistry

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