The structures of C-Ce2O3+δ, Ce7O12, and Ce11O20

被引:310
作者
Kümmerle, EA [1 ]
Heger, G
机构
[1] Univ Aachen, Inst Crystallog, Aachen, Germany
[2] Inst Solid Solid State Res Ctr Julich, Julich, Germany
关键词
D O I
10.1006/jssc.1999.8403
中图分类号
O61 [无机化学];
学科分类号
070301 ; 081704 ;
摘要
The crystal structures of CeO1.68 (C-Ce2O3+delta), Ce7O12, and Ce11O20 with ordered oxygen vacancy distributions have been determined by refinement of single crystal neutron diffraction data collected at ambient temperature. CeO1.68 is cubic, of space group Ia (3) over bar with a = 11.111(2) Angstrom; one of the two oxygen positions is partially occupied with a probability of 37(3)%. For Ce7O12 the rhombohedral space group R (3) over bar with a 6.785(1) Angstrom, alpha = 99.42(1)degrees was confirmed. Ce11O20 is isomorphous to Tb11O20 with the triclinic space group P (1) over bar. The lattice parameters are a 6.757(3) Angstrom, b = 10.260(5) Angstrom, c = 6.732(3) Angstrom, alpha = 90.04(4)degrees, beta = 99.80(4)degrees, and gamma = 96.22(4)degrees. For Ce11O20 there are no 1/2[1,1,1](F) oxygen vacancy pairs, i.e., pairs corresponding to half of the space diagonal of the fluorite lattice along [1, 1, 1](F). The shortest vacancy pair type in that structure is 1/2[1, 1, 1](F), which is also present in the two other phases. High temperature neutron diffraction measurements showed that Ce7O12 is stable up to 1072 K. Then it transforms into a fluorite type structure with disordered oxygen vacancies. (C) 1999 Academic Press.
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页码:485 / 500
页数:16
相关论文
共 17 条
[1]   MIXED OXIDES OF THE TYPE MO2 (FLUORITE)-M2O3 .1. OXYGEN DISSOCIATION PRESSURES AND PHASE RELATIONSHIPS IN THE SYSTEM CEO2-CE2O3 AT HIGH TEMPERATURES [J].
BEVAN, DJM ;
KORDIS, J .
JOURNAL OF INORGANIC & NUCLEAR CHEMISTRY, 1964, 26 (09) :1509-1523
[2]   ORDERED INTERMEDIATE PHASES IN THE SYSTEM CEO2-CE2O3 [J].
BEVAN, DJM .
JOURNAL OF INORGANIC & NUCLEAR CHEMISTRY, 1955, 1 (1-2) :49-&
[3]   A HIGH-TEMPERATURE LATTICE-PARAMETER AND DILATOMETER STUDY OF THE DEFECT STRUCTURE OF NONSTOICHIOMETRIC CERIUM DIOXIDE [J].
CHIANG, HW ;
BLUMENTHAL, RN ;
FOURNELLE, RA .
SOLID STATE IONICS, 1993, 66 (1-2) :85-95
[4]   RARE-EARTH HYDRIDES AND RARE-EARTH OXIDES IN AND FROM THIN-FILMS OF RARE-EARTH METALS [J].
GASGNIER, M ;
GHYS, J ;
SCHIFFMACHER, G ;
LABLANCH.CH ;
CARO, PE ;
BOULESTEIX, C ;
LOIER, C ;
PARDO, B .
JOURNAL OF THE LESS-COMMON METALS, 1974, 34 (01) :131-142
[5]   PREPARATION AND ELECTRON-MICROSCOPY OF INTERMEDIATE PHASES IN THE INTERVAL CE7O12-CE11O20 [J].
KNAPPE, P ;
EYRING, L .
JOURNAL OF SOLID STATE CHEMISTRY, 1985, 58 (03) :312-324
[6]  
KUMMERLE E, 1998, JUL3576
[7]  
KUMMERLE EA, UNPUB
[8]  
*OAK RIDG NAT LAB, ORTEP 3 OAK RIDG THE
[9]   REDUCTION OF CERIAS WITH DIFFERENT TEXTURES BY HYDROGEN AND THEIR REOXIDATION BY OXYGEN [J].
PERRICHON, V ;
LAACHIR, A ;
BERGERET, G ;
FRETY, R ;
TOURNAYAN, L ;
TOURET, O .
JOURNAL OF THE CHEMICAL SOCIETY-FARADAY TRANSACTIONS, 1994, 90 (05) :773-781
[10]   X-RAY AND NEUTRON-DIFFRACTION STUDY OF INTERMEDIATE PHASES IN NONSTOICHIOMETRIC CERIUM DIOXIDE [J].
RAY, SP ;
NOWICK, AS ;
COX, DE .
JOURNAL OF SOLID STATE CHEMISTRY, 1975, 15 (04) :344-351