Crystal Structure of a Layered Perovskite Niobate KCa2Nb3O10

✍ Scribed by Hiroshi Fukuoka; Toshiyuki Isami; Shoji Yamanaka

• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 299 KB
• Volume: 151
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.2000.8619

✦ Synopsis

The crystal structure of a layered perovskite niobate KCa 2 Nb 3 O 10 was investigated through single-crystal X-ray analysis. The niobate crystallized in the orthorhombic system Cmcm with lattice constants of a ‫؍‬ 3.8802(9) A s , b ‫؍‬ 29.508(6) A s , c ‫؍‬ 7.714(1) A s , V ‫؍‬ 883.2(2) A s 3 . The 5nal re5nement using the 908 independent re6ections converged into R ‫؍‬ 4.1%, and R w ‫؍‬ 4.7%. The structure of KCa 2 Nb 3 O 10 was composed of triple-layered perovskite slabs, potassium ions being situated between the slabs. The adjacent perovskite slabs, stacking along the c axis, were mutually displaced with a displacement vector of al /2. The potassium ions were coordinated by six oxygen atoms to form two short and four long bonds. Apparent disordering was observed in the equatorial oxygen sites of the central niobium atoms in the triple perovskite slabs.