Synthesis and Crystal Structures of BaLaSi2 with cis鈥搕rans Si Chains and Ba5LaSi6 with Pentagonal Si Rings

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• 作者：Takayuki Hashimoto ; Hisanori Yamane ; Takahiro Yamada ; Takashi Sekiguchi
• 刊名：Inorganic Chemistry
• 出版年：2015
• 出版时间：September 21, 2015
• 年：2015
• 卷：54
• 期：18
• 页码：9188-9194
• 全文大小：377K
• ISSN：1520-510X

文摘

Prismatic single crystals of novel compounds BaLaSi₂ and Ba₅LaSi₆ were synthesized from the elements with or without a Na flux. The crystal structures of the compounds were analyzed by X-ray diffraction. BaLaSi₂, containing cis鈥搕rans _{鈭?/sub>¹[Si] chains, crystallizes in an orthorhombic cell (a = 4.6414(2) 脜, b = 14.8851(7) 脜, c = 6.7519(5) 脜; space group, Cmcm (No. 63), Z = 4) and is isotypic with the low-temperature phase of LaSi. The crystal structure of Ba5LaSi6 (a = 17.1447(5) 脜, b = 4.8767(1) 脜, and c = 17.9102(4) 脜; space group Pnma (No. 62), Z = 4) is a new type containing isolated anionic groups (⁰[Si5鈥揝i]) of a pentagonal Si ring with a Si鈥揝i stem. The electrical resistivities measured for the polycrystalline BaLaSi2 and Ba5LaSi6 sintered samples were 0.31 and 0.48 m惟路cm, respectively, at 300 K and increased with temperature. The Seebeck coefficients of BaLaSi2 and Ba5LaSi6 were 鈭?.6 and 鈭?1 渭V路K^鈥?, respectively, at 296 K.}