Crystal structure of the arsenate NaNb4O9AsO4. A framework structure with diffusion pathways

✍ Scribed by N. Bestaoui; A. Verbaere; Y. Piffard; V. Coulibaly; J. Zah-Letho

• Book ID: 104372697
• Publisher: Elsevier Science
• Year: 1998
• Tongue: English
• Weight: 491 KB
• Volume: 35
• Category: Article
• ISSN: 0992-4361
• DOI: 10.1016/s0992-4361(98)80024-6

✦ Synopsis

Single crystals of NaNb.,O&Od ,were prepared. by solid state reaction at 875°C from a mixture of NaNO,, Nb,05 and NH,H&sO,. NaNbaO&O, crystallizes in the or&rhombic system, space group Prima, 2=4, with a=9.9858(7) A, b=10.3811(6) A, c=10.4107(6) A. The diffraction intensities were collected on a Siemens P4 diffractomete with MoKa radiation. The crystal structure was determined and refined from 3465 independent &kctions. The threedimensiona.l fmmework consists of infinite chains (-MO,-~&04-),, parallel to the b axis and crosslinked via comer sharing by pairs of edge-sharmg octahedra. Each pair links four chains. The Na ion partially occupies several independent close positions, with various occupancies, in the interconnected cavities delimited by the framework.