| Autor: |
Gourdon O; Laboratoire de Chimie des Solides, IMN, UMR C6502 CNRS - Université de Nantes, 2 rue de la Houssinière, BP 32229, 44322 Nantes Cedex 3, France., Petricek V V, Dusek M, Bezdicka P, Durovic S, Gyepesova D, Evain M |
| Jazyk: |
angličtina |
| Zdroj: |
Acta crystallographica. Section B, Structural science [Acta Crystallogr B] 1999 Dec 01; Vol. 55 (Pt 6), pp. 841-848. |
| DOI: |
10.1107/s0108768199006485 |
| Abstrakt: |
Sr(14/11)CoO(3) (i.e. Sr(14)Co(11)O(33), tetradecastrontium undecacobalt tritriacontaoxide), a new phase in the hexagonal perovskite Sr(x)CoO(3) system, has been prepared and its structure solved from single-crystal X-ray data within the (3 + 1)-dimensional formalism. Sr(14/11)CoO(3) crystallizes in the trigonal symmetry, R3;m(00gamma)0s superspace group with the following lattice parameters: a(s) = 9.508 (2), c(s) = 2.5343 (7) Å, q = 0.63646 (11)c(*) and V(s) = 198.40 (13) Å(3). With the commensurate versus incommensurate test not being conclusive, the structure was considered as commensurate (P32 three-dimensional space group), but refined within the (3 + 1)-dimensional formalism to a residual factor R = 0.0351 for 47 parameters and 1169 independent reflections. Crenel functions were used for the oxygen and cobalt description and a Gram-Charlier expansion up to the third order of the atomic displacement parameter was employed for one Co atom. The structure is similar to that of Sr(6/5)CoO(3), but with a different sequence of the octahedra and trigonal prism polyhedra along the [CoO(3)] chains. An interesting feature evidenced by the non-harmonic expansion is the displacement of the prismatic Co atoms from the site center, towards the prism rectangular faces. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
|
Plný text