Clathrates of group 14 with alkali metals: An exploration
Clathrates of group 14 with alkali metals: An exploration
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DOI：
10.1006/jssc.2000.8755
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发表时间：
2000-08-01
影响因子：
3.3
通讯作者：
Sevov, SC
中科院分区：
文献类型：
--
作者：
Bobev, S;Sevov, SC
报告了四种具有笼形 II 结构的硅和锗化合物 Cs8Na16Si136 (1)、Cs8Na16Ge136 (2)、Rb8Na16Si136 (3) 和 Rb8Na16Ge36 (4) 的定量合成及其表征。相应的 Si-Si 和 Ge-Ge 距离是通过大量的单晶 X 射线衍射工作高精度确定的。这些化合物（立方体，空间群 Fd(3) 超过 bar m，a = 14.7560(4)、15.4805(6)、14.7400(4) 和 15.4858(6) 埃，分别为 1、2、3 和 4）是化学计量的、金属的，并且非常稳定。没有发现硅和锗网络中存在空位或碱金属位点部分占据的证据。这些完全填充的包合物的化学计量与测量的与温度无关的泡利顺磁性（对于1、2、3和4分别为chi = 7.2 x 10(-4)、6.5 x 10(-4)、6.9 x 10(-5)和1.4 x 10(-4) emu/mol）和金属电阻率（rho(293)近似于10(-5) 欧米茄-厘米)。 (C) 2000 年学术出版社。
The quantitative synthesis of four silicon and germanium compounds with the clathrate-II structure, Cs8Na16Si136 (1), Cs8Na16Ge136 (2), Rb8Na16Si136 (3), and Rb8Na16Ge36 (4), and their characterizations are reported. The corresponding Si-Si and Ge-Ge distances are determined with high accuracy from extensive single-crystal X-ray diffraction work. The compounds (cubic, space group Fd(3) over bar m, a = 14.7560(4), 15.4805(6), 14.7400(4), and 15.4858(6) Angstrom for 1, 2, 3, and 4, respectively) are stoichiometric, metallic, and remarkably stable. No evidence was found for vacancies in the silicon and germanium networks or partial occupancies of the alkali metal sites. The stoichiometry of these completely filled clathrates is consistent with the measured temperature-independent Pauli paramagnetism (chi = 7.2 x 10(-4), 6.5 x 10(-4), 6.9 x 10(-5), and 1.4 x 10(-4) emu/mol for 1, 2, 3, and 4, respectively) and metallic resistivity (rho(293) approximate to 10(-5) Omega-cm). (C) 2000 Academic Press.