文献类型：期刊文献

英文题名：The 2a0 x 2a0 x 2a0 Superstructure in the Clathrate-I K8LixGe44-x/4□2-3x/4

作者：Liang, Ying[1];Carrillo-Cabrera, Whilder[2];Ormeci, Alim[2];Boehme, Bodo[2];Baitinger, Michael[2];Grin, Yuri[2]

机构：[1]E China Univ Sci & Technol, Inst Nucl Technol & Applicat, Sch Sci, Shanghai 200237, Peoples R China;[2]Max Planck Inst Chem Phys Fester Stoffe, D-01187 Dresden, Germany

年份：2015

卷号：641

期号：2

起止页码：339

外文期刊名：ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE

收录：;WOS:【SCI-EXPANDED(收录号:WOS:000351444500033)】；

基金：Y.L. acknowledges financial support by the National Natural Science Foundation of China (No. 51301071), the Science and Technology Commission of Shanghai Municipality (No. 13PJ1401800) and the Innovation Program of Shanghai Municipal Education Commission (No. 14ZZ057). B.B., M.B. and Y.G. acknowledge financial support by the Deutsche Forschungsgemeinschaft (DFG) within the priority program SPP1415. We thank the Competence Groups Struktur and Chemische Analyse at the MPI CPfS for X-ray diffraction experiments and chemical analyses, respectively.

语种：英文

外文关键词：Intermetallic phases; Clathrates; X-ray diffraction; Crystal structure; Superstructure

摘要：In the crystal structure of the clathrate-I K8LixGe44-x/4 square(2-3x/4), the K atoms fill the polyhedral cages of a host framework formed by Li and Ge atoms. The phase has been obtained in two forms, at elevated temperatures with space group Pm (3) over bar n, and at low temperatures with a 2a(0) x 2a(0) x 2a(0) superstructure. In this work, we report on the direct preparation of the low-temperature form by thermal decomposition of the precursor phase K7LiGe8 at 400 degrees C. The obtained product K8Li2.48(7)Ge43.37(9)square(0.15(6)) [a = 21.5489(2)angstrom, Z = 8] was found to be virtually identical with the one prepared by annealing of the hightemperature form at this temperature. The superstructure was investigated by X-ray powder diffraction and transmission electron microscopy, revealing the space group Ia3 _ d. The low-temperature form of K8LixGe44-x/4 square(2-3x/4) represents one of the rare examples for a clathrate-I superstructure primarily caused by an ordered arrangement of heteroatoms. Two similar, yet inequivalent models for the description of the ordering of lithium atoms in the framework are discussed.