Type-I clathrates of K7.69(2)Cu2.94(6)Ge43.06(6) and Rb8Ag2.79(4)Ge43.21(4)

Hui Zhang; Xuguang Xu; Wei Li; Gang Mu; Fu-Qiang Huang; Xiao-Ming Xie

doi:10.1039/C5RA09382A

Type-I clathrates of K_7.69(2)Cu_2.94(6)Ge_43.06(6) and Rb₈Ag_2.79(4)Ge_43.21(4)†

Hui Zhang,^a Xuguang Xu,^b Wei Li,^b Gang Mu,^b Fu-Qiang Huang*^ac and Xiao-Ming Xie^b

* Corresponding authors

^a CAS Key Laboratory of Materials for Energy Conversion, State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, P. R. China
E-mail: huangfq@mail.sic.ac.cn
Tel: +86-21-52411620

^b State Key Laboratory of Functional Materials for Informatics and Shanghai Center for Superconductivity, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, P. R. China

^c Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China

Abstract

Type-I clathrates of K_7.69(2)Cu_2.94(6)Ge_43.06(6) and Rb₈Ag_2.79(4)Ge_43.21(4) are synthesized directly from the corresponding elements. The structures are resolved by powder XRD data by means of a least-squares technique using WinCSD program. The refined lattice parameters are a = 10.70783(3) Å and a = 10.84493(3) Å for K_7.69(2)Cu_2.94(6)Ge_43.06(6) and Rb₈Ag_2.79(4)Ge_43.21(4), respectively. The electronic band structure and density of states indicate K₈Cu₃Ge₄₃ and Rb₈Ag₃Ge₄₃ are p-type semiconductors with narrow indirect band gaps of 0.33 and 0.24 eV. In addition, K_7.69(2)Cu_2.94(6)Ge_43.06(6) displays a diamagnetism with χ = −1.102(1) × 10⁻³ emu mol⁻¹ in the field of 7 T at 400 K and has a strong Einstein model with θ_E = 56.3(1) K and θ_D = 297(3) K.

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Article information

DOI: https://doi.org/10.1039/C5RA09382A
Article type: Paper
Submitted: 19 May 2015
Accepted: 09 Jun 2015
First published: 09 Jun 2015

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RSC Adv., 2015,5, 53829-53834

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Type-I clathrates of K_7.69(2)Cu_2.94(6)Ge_43.06(6) and Rb₈Ag_2.79(4)Ge_43.21(4)

H. Zhang, X. Xu, W. Li, G. Mu, F. Huang and X. Xie, RSC Adv., 2015, 5, 53829 DOI: 10.1039/C5RA09382A

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