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Crystal Structure Investigations and Thermal Behavior of the Five‐Leg Spin Ladder Compound La 8 Cu 7 O 19
Author(s) -
Schüpp Barbara,
Sekar Chinnathambi,
Gruner Wolfgang,
Auffermann Gudrun,
Bähtz Carsten,
Krabbes Gernot
Publication year - 2004
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.200300424
Subject(s) - crystallography , monoclinic crystal system , crystal structure , octahedron , rietveld refinement , lanthanum , materials science , lattice energy , neutron diffraction , tetragonal crystal system , chemistry , inorganic chemistry
La 8 Cu 7 O 19 was synthesized by solid state reaction of the oxides La 2 O 3 and CuO at 1288 K in air. The crystal structure was determined by a joint Rietveld refinement of X‐ray and neutron powder diffraction data. La 8 Cu 7 O 19 crystallizes in the monoclinic space group C 2/ c (No. 15) with the lattice parameters a = 13.8310(4)Å, b = 3.75827(9)Å, c = 34.5917(8)Å and β = 99.332(2)°. La 8 Cu 7 O 19 is the n = 3 member of the homologous series La 4+4 n Cu 8+2 n O 14+8 n . The Cu—O sub‐structure in La 8 Cu 7 O 19 contains infinite ribbons, which can be described as perovskite type layers with a width of n = 3 Jahn‐Teller‐elongated octahedra, and Cu—O planes of complex geometry. DSC/TG‐measurements in different gas atmospheres show peritectic decomposition of La 8 Cu 7 O 19 . The anisotropic thermal expansion of the lattice parameters was investigated using synchrotron radiation. The Madelung part of lattice energy was calculated and compared with the corresponding values of other lanthanum cuprates.