The synthesis and structural characterization of Sr sub 2 CuO sub 4 minus x , x @ 0. 1

Journal Article · Mon Oct 01 04:00:00 EDT 1990 · Journal of Solid State Chemistry; (USA)

DOI:https://doi.org/10.1016/0022-4596(90)90248-V· OSTI ID:6085506

Lobo, R C; Berry, F J; Greaves, C ^[1]

---

1. Univ. of Birmingham (England)

Sr{sub 2}CuO{sub 3} (orthorhombic, Immm) is converted at about 400{degree}C under oxygen at 160 bar to Sr{sub 2}CuO{sub 3.9} (tetragonal, I4/mmm; a = 3.7907(7), c = 12.417(2) {angstrom}), which is structurally related to La{sub 2}CuO{sub 4}. Although the formal Cu oxidation state in this material appears to be higher than any previously reported for Cu in an oxide environment (around +3.8), powder neutron diffraction data provide no evidence for O{sub 2}{sup 2{minus}} or O{sub 2}{sup {minus}} ions, but are consistent with a highly defective structure containing Sr, Cu, and O vacancies. The cation vacancies are in a 2:1 ratio to maintain the stoichiometry, and the O vacancies are confined to the CuO{sub 2} layers. Additional peaks in the neutron diffraction profile are indicative of an ordering process to give an extended, possibly incommensurate, structure. CuK-edge EXAFS suggests that the resulting local Cu coordination contains two very short Cu-O bonds (1.755 {angstrom}).

• OSTI ID: 6085506
• Journal Information: Journal of Solid State Chemistry; (USA), Journal Name: Journal of Solid State Chemistry; (USA) Vol. 88:2; ISSN 0022-4596; ISSN JSSCB
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360201* -- Ceramics
Cermets
& Refractories-- Preparation & Fabrication
360202 -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
656100 -- Condensed Matter Physics-- Superconductivity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALKALINE EARTH METALS
CHEMICAL PREPARATION
COHERENT SCATTERING
COPPER COMPOUNDS
CRYSTAL STRUCTURE
CUPRATES
DIFFRACTION
ELEMENTS
HIGH-TC SUPERCONDUCTORS
METALS
NEUTRON DIFFRACTION
OXYGEN COMPOUNDS
PHASE STUDIES
SCATTERING
STRONTIUM
SUPERCONDUCTORS
SYNTHESIS
TRANSITION ELEMENT COMPOUNDS