Crystal Structure of Ca4.78Cu6O11.60

✍ Scribed by Ph. Galez; M. Lomello-Tafin; Th. Hopfinger; Ch. Opagiste; Ch. Bertrand

• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 453 KB
• Volume: 151
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1999.8631

✦ Synopsis

The crystal structure of Ca 4.78 Cu 6 O 11.60 (crystal system, monoclinic; space group P2/c, Z ‫؍‬ 4, ‫؍‬ 4.48(2) g/cm 3 , a ‫؍‬ 10.9456(4) A s , b ‫؍‬ 6.3192(2) A s , c ‫؍‬ 16.8408(5) A s , and ‫؍‬ 104.952(2)3) has been solved and re5ned using X-ray and neutron powder di4raction combined with Rietveld analysis. It is closely related to the NaCuO 2 -type structure. The phase stoichiometry and the displacements of atoms with respect to their positions in the previously reported substructure (crystal system, orthorhombic; space group, Fmmm, a ‫؍‬ 2.807(1) A s , b ‫؍‬ 6.351(2) A s , and c ‫؍‬ 10.597(3) A s ) are explained by the minimization of Ca+Ca repulsion and by a relaxation toward a more regular octahedral environment for Ca atoms. The substitution of Tl atoms for Ca atoms results in an increased thermal stability and in incommensurate structures with modulation vectors depending strongly on the Tl content.