The Oxide Ba6Ga2Co11O26: A New Close-Packed Stacking Derived from the Hexagonal Perovskite

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• 作者：D. Pelloquin ; O. P&eacute ; rez ; G. Martinet ; S. H&eacute ; bert ; A. Maignan
• 刊名：Chemistry of Materials
• 出版年：2007
• 出版时间：May 15, 2007
• 年：2007
• 卷：19
• 期：10
• 页码：2658 - 2662
• 全文大小：278K
• 年卷期：v.19,no.10(May 15, 2007)
• ISSN：1520-5002

文摘

Single crystals of a new compound, Ba₆Ga₂Co₁₁O₂₆, have been grown by a self-flux method. Thestructure determined by single-crystal X-ray diffraction and transmission electron microscopy (TEM)techniques shows a complex intergrowth between an hexagonal perovskite block, corresponding to the5H term, and a complex block [Ba(Ga,Co)₈O₁₁]. It crystallizes in the Pges/entities/thremacr.gif">m1 trigonal space group with thefollowing unit-cell parameters: a = 5.652(2) Å, b = 5.652(2) Å, c = 18.828(8) Å, and ges/gifchars/gamma.gif" BORDER=0 > = 120ges/entities/deg.gif">. Thestructural analogy with two structural types, namely rocksalt and nolanite, allows a description of thenature of the [Ba(Ga,Co)₈O₁₁] block: one central [111]^RS Co₄O₈ slab, related to a CdI₂-type slice, issandwiched between two Ba(Ga,Co)₂O₃ nolanite-type slabs containing (Co/Ga)O₄ tetrahedra and(Co/Ga)O₆ octahedra. This compound can be thus viewed as the n = 5 member of the large series[Ba(Ga,Co)₈O₁₁][BaCoO₃]_n, opening the route toward the discovery of new cobaltites.