Superspace Description of NaCa4Nb5O17as a Modulated Layered Compound

Autor:	Luis Elcoro, J. M. Perez-Mato, F. J. Zuniga
Rok vydání:	2004
Předmět:	Crystallography Materials science Series (mathematics) Modulation (music) Structure (category theory) Wave vector Crystal structure Condensed Matter Physics Superspace Space (mathematics) Stoichiometry Electronic Optical and Magnetic Materials
Zdroj:	Ferroelectrics. 305:111-114
ISSN:	1563-5112 0015-0193
DOI:	10.1080/00150190490462513
Popis:	Following the general model proposed for the series of compounds Sr n (Nb,Ti) n O3n + 2 , the recently determined structure of the related compound NaCa 4 Nb 5 O 17 has been re-analyzed in superspace and refined using a set of crenel occupational functions. The atomic positions in real space can be described using eight independent atomic domains with smooth modulations under the superpace monoclinic symmetry X112 1 /b(α β 0) (X standing for the centring translations generated from (3/4 1/2 0 1/4)), and with modulation wave vector q = 1/12 b* (α = 0, β = 1/12). A refinement performed with the JANA2000 program using the same experimental data as the standard three-dimensional refinement gave indeed equivalent results. The superspace approach, however, reduced the number of structural variables.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::ba5b8ff41db069c9bd75135738aa4770 https://doi.org/10.1080/00150190490462513 Zobrazit plný text záznamu