X- and neutron diffraction study of UCr/sub 2/O/sub 6/ monocrystal. Determination of crystallographical and magnetic structures

Journal Article · Thu Jan 01 04:00:00 EST 1976 · J. Solid State Chem.; (United States)

DOI:https://doi.org/10.1016/0022-4596(76)90005-0· OSTI ID:7365377

Collomb, A ^[1]; Gondrand, M; Lehmann, M S; Capponi, J J; Joubert, J C

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1. CNRS, Grenoble, France

The structure of UCr/sub 2/O/sub 6/, PbSb/sub 2/O/sub 6/ type compound was refined from x-ray and neutron single crystal data. The symmetry is trigonal, space group P31m. The lattice parameters are a = 4.990 (1) A; c = 4.622 (1)A. There is one molecule per unit cell. The uranium, chromium, and oxygen atoms occupy the 1a (0,0,0), 2d(1/3, 2/3, 1/2), 6k(x,0,z) positions, respectively, with x = 0.3405 (3) and z = 0.2647 (2). The final R factors are 0.033 for the x-ray data and 0.0294 for the neutron data. The anisotropic temperature factors have been introduced in last stage of both refinements. The average cation-anion interatomic distances are U--O = 2.094 (1) A, Cr--O = 1.9726 (8) A. From these values it can be deduced that the uranium and chromium are hexavalent and trivalent respectively. From powder diffraction diagrams at 298 and 4.2/sup 0/K, it has been determined that the spin of the Cr/sup 3 +/ are located in the basal plane with an antiferromagnetic type arrangement. The value of the magnetic moment is 2.6 ..mu..B. (auth)

• OSTI ID: 7365377
• Journal Information: J. Solid State Chem.; (United States), Journal Name: J. Solid State Chem.; (United States) Vol. 16:1-2; ISSN JSSCB
• Country of Publication: United States
• Language: French

Related Subjects

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400702* -- Radiochemistry & Nuclear Chemistry-- Properties of Radioactive Materials
ACTINIDE COMPOUNDS
ANGULAR MOMENTUM
BOND LENGTHS
CHROMATES
CHROMIUM COMPOUNDS
COHERENT SCATTERING
CRYSTAL STRUCTURE
CRYSTALS
DIFFRACTION
LATTICE PARAMETERS
MAGNETIC MOMENTS
MAGNETIC PROPERTIES
MONOCRYSTALS
NEUTRON DIFFRACTION
OXYGEN COMPOUNDS
PARTICLE PROPERTIES
PHYSICAL PROPERTIES
SCATTERING
SPIN
TRANSITION ELEMENT COMPOUNDS
URANIUM COMPOUNDS
X-RAY DIFFRACTION