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[Bi12O14E12]nColumns and Lone PairsEin Bi13Mo4VO34E13: Synthesis, Crystal Structure, and Chemistry of the Bi2O3–MoO3–V2O5System

1997; Elsevier BV; Volume: 131; Issue: 2 Linguagem: Inglês

10.1006/jssc.1997.7367

1095-726X

Renée Enjalbert, Georg Hasselmann, Jean Galy,

Crystal Structures and Properties

A new phase, Bi13Mo4VO34E13(E: Bi(III) lone pair) was found in the Bi2O3–MoO3–V2O5system and its formula determined via single crystal analysis and confirmed by solid state synthesis. It crystallizes in the monoclinic system, space groupP2/c, with cell parametersa=11.652(7)Å,b=5.7923(8)Å,c=24.420(9)Å,β=101.38(6)°, andZ=2. The crystal structure is built up by infinite [Bi12O14E12]ncolumns surrounded by 10 (Mo,V)O4tetrahedra, situated on layers parallel to (100) and (001), with an extra Bi atom located at the intersection of these “(Mo,V)O4layers” in between two tetrahedra. The Bi13Mo4VO34E13structure is in general agreement with that of R. N. Vannieret al.(1996,J. Solid State Chem.111, 118) giving a structural formulation Bi26M10O68but with their chemical formulations giving Bi26Mo10O69or Bi26Mo6V4O67and hypothetical nonstoichiometry Bi26M10Oδ. Taking into account the cell dimensions and structural details of Bi13Mo4VO34E13, which show that a reported phase like Bi6Mo2O15could also be isostructural, a new hypothesis based on the possible replacement of BiO4Etrigonal bipyramid and/or BiO3Etetrahedra for MoO4tetrahedra strengthens the probability that there is a continuous solid solution in the Bi2O3–MoO3system between the compositions 1.43 Bi2O3: 1 MoO3and 1.75 Bi2O3: 1 MoO3. Synthesis and cell dimensions of various compositions supporting these ideas are given. The domain of existence for such phases can extend in the pseudo-ternary Bi2O3–MoO3–V2O5system up to the phase Bi13Mo4VO34; this triangular area excludes Bi26Mo10O69and Bi26Mo6V4O67compositions.