Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Synthesis and Single-Crystal X-Ray Diffraction Studies of New Framework Substituted Type II Clathrates, Cs8Na16AgxGe136-x (x

Published

Author(s)

Matthew Beekman, Winnie K. Wong-Ng, James A. Kaduk, Alexander J. Shapiro, George S. Nolas

Abstract

New inorganic type II clathrates with Ag atoms substituting for framework Ge atoms, Cs8Na16AgxGe136-x (x = 0, 5.9, and 6.7), have been synthesized by reaction of the pure elements at high temperature. Structural refinements have been performed using single crystal X-ray diffraction. The materials crystallize with the cubic type II clathrate crystal structure (space group Fd-3m) with a = 15.49262(9) , 15.51605(6) , and 15.51618(9) for x = 0, 5.9, and 6.7, respectively, and Z = 1. The structure is formed by a covalently bonded Ag-Ge framework, in which the Cs and Na atoms are found inside two types of polyhedral cages. Ag substitutes for Ge in the tetrahedrally bonded framework positions, and was found to preferentially occupy the most asymmetric 96g site. The proven ability to substitute atoms for the germanium framework should offer a route to the synthesis of new compositions of type II clathrates, materials that are of interest for potential thermoelectrics applications.
Citation
Journal of Solid State Chemistry

Keywords

Ag, clathrate, framework compound, Ge, X-ray diffraction

Citation

Beekman, M. , Wong-Ng, W. , A., J. , Shapiro, A. and Nolas, G. (2007), Synthesis and Single-Crystal X-Ray Diffraction Studies of New Framework Substituted Type II Clathrates, Cs<sub>8</sub>Na<sub>16</sub>Ag<sub>x</sub>Ge<sub>136-x</sub> (x < 7), Journal of Solid State Chemistry (Accessed August 5, 2021)
Created April 13, 2007, Updated February 19, 2017