Relations between oxygen deficiency and structures in the La-Sr-Cu-O system. II. A new oxygen-deficient phase (La, Sr)[sub 4]Cu[sub 4]O[sub 10]

Journal Article · Mon Nov 01 04:00:00 EST 1993 · Journal of Solid State Chemistry; (United States)

DOI:https://doi.org/10.1006/jssc.1993.1332· OSTI ID:7274279

Otzschi, Kenji; Ueda, Yutaka ^[1]

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1. Institute for Solid State Physics, Univ. of Tokyo, Tokyo (Japan)

The authors report the synthesis and the structural properties of a new oxygen-deficient perovskite with the formula (La[sub 1[minus]x]Sr[sub x])[sub 4]Cu[sub 4]O[sub 10](x = 0.1429) (Sr/La = 1/6): 4-4-10. It crystallizes in an orthorhomobic cell with the parameters a [approx] 2[radical] 2a[sub p], b [approx] [radical] 2a[sub p], and c [approx] A[sub p], where a[sub p] means the cell constant of an ideal cubic perovskite. According to the crystal structure which has been refined in the space Pbam by Rietvald analysis of powder X-ray diffraction (XRD), it has the same structure as CaMnO[sub 2.5], and lanthanum and strontium ions in the structure are statistically distributed as well as the other compounds, (La[sub 1[minus]x]Sr[sub x])[sub 8]Cu[sub 8]O[sub 20] (0.16 [le] x [le] 0.24:8-8-20) and (La[sub 1[minus]x]Sr[sub x])[sub 5]Cu[sub 5]O[sub 13] (x = 0.666 (Sr/La = 1/5):5-5-13). This newly found 4-4-10 compound, however, is constituted by only one type of Cu-O polyhedron, i.e., CuO[sub 5] pyramids, while the 8-8-20 and the 5-5-13 compounds include CuO[sub 6] octahedra and/or CuO[sub 4] squares in the structure as well. TG-DTA study and XRD measurement at high temperature revealed the structural phase transition of 4-4-10 to 8-8-20 around 550[degrees]C without any gain or loss of oxygen. Some physical properties are also reported.

• OSTI ID: 7274279
• Journal Information: Journal of Solid State Chemistry; (United States), Journal Name: Journal of Solid State Chemistry; (United States) Vol. 107:1; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
360204 -- Ceramics
Cermets
& Refractories-- Physical Properties
ALKALINE EARTH METAL COMPOUNDS
CHALCOGENIDES
CHEMICAL PREPARATION
COPPER COMPOUNDS
COPPER OXIDES
CRYSTAL LATTICES
CRYSTAL STRUCTURE
DIFFERENTIAL THERMAL ANALYSIS
LANTHANUM COMPOUNDS
LANTHANUM OXIDES
LATTICE PARAMETERS
ORTHORHOMBIC LATTICES
OXIDES
OXYGEN COMPOUNDS
PHASE STUDIES
PHASE TRANSFORMATIONS
RADICALS
RARE EARTH COMPOUNDS
STOICHIOMETRY
STRONTIUM COMPOUNDS
STRONTIUM OXIDES
STRUCTURAL CHEMICAL ANALYSIS
SYNTHESIS
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE
TEMPERATURE RANGE 0273-0400 K
TEMPERATURE RANGE 0400-1000 K
THERMAL ANALYSIS
TRANSITION ELEMENT COMPOUNDS