Synthèse et structure cristalline de Rb5VONb14O38

✍ Scribed by Amor Haddad; Tahar Jouini

• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 392 KB
• Volume: 134
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1997.7507

✦ Synopsis

Rb 5 VONb 14 O 38 , M r ‫؍‬ 2403.03 g mol ؊1 , crystallizes in the hexagonal crystal system, space group P6 3 /mmc, Z ‫؍‬ 2. The lattice parameters are a ‫؍‬ 7.5150(2) A s and c ‫؍‬ 36.3540(8) A s , V ‫؍‬ 1778.04(8) A s 3 , D x ‫؍‬ 4.488 Mg m ؊3 . The crystal structure was refined from 665 independent reflections. The final R index and weighted R w index are 0.0285 and 0.0718, respectively. The title compound has a three-dimensional network, constituted by two types of layers, (Nb 6 O 15 ) n and (Nb 3 O 9 ) n , parallel to (0001). Those layers are linked together, in the c direction, according to the sequence (Nb 6 O 15 ) n -NbO 6 -(Nb 3 O 9 ) n -(Nb 3 O 9

) n -NbO 6 , by pooling corners of NbO 6 octahedra. V 3؉ ions are located in trigonal prismatic sites, between two Nb 3 O 9 units belonging to two neighboring (Nb 3 O 9 ) n layers. This framework has cavities which communicate with interconnected tunnels, parallel to the a axis. Rb ؉ ions are located in these cavities.