Crystal structures of Ca-free Pb[sub 2]Sr[sub 2]RCu[sub 3]O[sub 8] (R = La, Pr, Nd, Eu, Tb, and Dy) single crystals

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

DOI:https://doi.org/10.1006/jssc.1993.1062· OSTI ID:6518616

Xue, J S; Greedan, J E; Maric, M ^[1]

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1. McMaster Univ., Hamilton, Ontario (Canada)

Structures of Pb[sub 2]Sr[sub 2]RCu[sub 3]O[sub 8] have been determined by single crystal X-ray diffraction. A monoclinic symmetry (C2/m, Z = 2) was found for those crystals with R = Pr, Nd, and Tb, orthorhombic (Cmmm, Z = 2) for R = La, and tetragonal (P4/mmm, Z = 1) for R = Eu and Dy. The relationship among different crystal symmetries can be understood in terms of different oxygen orderings in the PbO layers driven by the Pb[sup 2+] lone pair orientation. There is evidence for a [approximately]9% deficiency in electron density at the R = Eu and Dy sites (and [approximately]4.5% for R = Tb) which has been confirmed by mass spectroscopy as being due to cation vacancies at these sites. Bond valence sum calculations have been performed to evaluate the strains existing in the crystal structures of Pb[sub 2]Sr[sub 2]RCu[sub 3]O[sub 8]. 28 refs., 8 figs., 5 tabs.

• OSTI ID: 6518616
• Journal Information: Journal of Solid State Chemistry; (United States), Journal Name: Journal of Solid State Chemistry; (United States) Vol. 102:2; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
ALKALINE EARTH METAL COMPOUNDS
CHALCOGENIDES
COHERENT SCATTERING
COPPER COMPOUNDS
COPPER OXIDES
CRYSTAL DEFECTS
CRYSTAL LATTICES
CRYSTAL STRUCTURE
DIFFRACTION
DYSPROSIUM COMPOUNDS
DYSPROSIUM OXIDES
ELECTRON DENSITY
EUROPIUM COMPOUNDS
EUROPIUM OXIDES
LANTHANUM COMPOUNDS
LANTHANUM OXIDES
LAYERS
LEAD COMPOUNDS
LEAD OXIDES
MASS SPECTROSCOPY
MATHEMATICAL MODELS
MONOCLINIC LATTICES
NEODYMIUM COMPOUNDS
NEODYMIUM OXIDES
ORTHORHOMBIC LATTICES
OXIDES
OXYGEN COMPOUNDS
POINT DEFECTS
PRASEODYMIUM COMPOUNDS
PRASEODYMIUM OXIDES
RARE EARTH COMPOUNDS
SCATTERING
SPECTROSCOPY
STRAINS
STRONTIUM COMPOUNDS
STRONTIUM OXIDES
TERBIUM COMPOUNDS
TERBIUM OXIDES
TETRAGONAL LATTICES
TRANSITION ELEMENT COMPOUNDS
VACANCIES
VALENCE
X-RAY DIFFRACTION