New Type-I and Type-II Clathrates in the Systems Cs–Na–Ga–Si, Rb–Na–Ga–Si, and Rb–Na–Zn–Si

Inorganics

Marion C. Schäfer¹  Svilen Bobev¹ 

[1] Department of Chemistry & Biochemistry, University of Delaware, Newark, DE 19716, USA;

关键词: clathrates;    type-I structure;    type-II structure;    silicon;   

DOI  :  10.3390/inorganics2010079

来源: DOAJ

【 摘 要 】

Systematic studies in the systems Cs–Na–Ga–Si, Rb–Na–Ga–Si, andRb–Na–Zn–Si yielded the novel type-I clathrates with refined compositions Cs6Na2Ga8.25Si37.75(3), Rb6.34Na1.66(2)Ga8.02Si37.98(3), and Rb5.20Na2.80(4)Zn3.85Si42.15(2) (cubic, ), as well as the type-II clathrates with formulae Cs8Na16Ga22.7Si113.3(1), Rb8.4Na15.6(1)Ga19.6Si116.4(1), and Rb8Na16Zn8.4Si127.6(1) (cubic,). In each system, the type-I and -II compounds are always co-crystallizing, irrespective of the reaction conditions. The structures derived from single-crystal X-ray diffraction confirm complete ordering of Cs and Na atoms, and nearly complete ordering of the Rb and Na guest atoms. The framework-building Si atoms are randomly substituted by Ga or Zn atoms on all framework sites with notable difference in the substitution patterns between the type-I and type-II structure. This, and other details of the crystal chemistry are discussed in this paper.

【 授权许可】

Unknown