Single-Crystal Growth and Structure Determination of a New Oxide Apatite, NaLa9(GeO4)6O2

✍ Scribed by Masaru Takahashi; Kazuyoshi Uematsu; Zuo-Guang Ye; Mineo Sato

• Publisher: Elsevier Science
• Year: 1998
• Tongue: English
• Weight: 432 KB
• Volume: 139
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1998.7845

✦ Synopsis

NaLa 9 Ge 6 O 26 , hexagonal, a ‫؍‬ 0.9883(2) nm, c ‫؍‬ 0.7267(3) nm, V ‫01؋)3(741.6؍‬ 5 nm 3 , space group P6 3 /m, Z ‫؍‬ 1, D calc ‫؍‬ 5.739 g cm ؊3 , (MoK ) ‫؍‬ 0.071069 nm, ‫؍‬ 225.16 cm ؊1 , F(000) ‫؍‬ 924, T ‫؍‬ 298 K, R ‫؍‬ 0.031, R w ‫؍‬ 0.037 for 966 measured unique reflections. Single crystals of NaLa 9 Ge 6 O 26 were grown both by a high-temperature flux method and from a melt system. The crystal structure was found to be similar to that of the silicate oxyapatite NaY 9 Si 6 O 26 . The 4 f cation sites are occupied disorderedly by La and Na. On the other hand, the 6h cation sites are occupied by La only. This compound constitutes a new member of the oxyapatite-type structure family with general formula A x Ln 10؊x B 6 O 24 O 3؊x (x ‫؍‬ 1, A ‫؍‬ alkali metals, B ‫؍‬ Si, Ge, Ln ‫؍‬ rare earth).