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Title: Synthesis and single-crystal X-ray diffraction studies of new framework substituted type II clathrates, Cs{sub 8}Na{sub 16}Ag{sub x}Ge{sub 136-x} (x<7)

Abstract

New inorganic type II clathrates with Ag atoms substituting for framework Ge atoms, Cs{sub 8}Na{sub 16}Ag{sub x}Ge{sub 136-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 Fd3-barm) with a=15.49262(9)A, 15.51605(6)A, 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.

Authors:
 [1];  [2];  [3];  [2];  [4]
  1. Department of Physics, University of South Florida, 4202 East Fowler Ave., PHY 114, Tampa, FL 33620 (United States)
  2. Materials Science and Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States)
  3. INEOS Technologies, Naperville, IL 60566 (United States)
  4. Department of Physics, University of South Florida, 4202 East Fowler Ave., PHY 114, Tampa, FL 33620 (United States), E-mail: gnolas@cas.usf.edu
Publication Date:
OSTI Identifier:
21015749
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 180; Journal Issue: 3; Other Information: DOI: 10.1016/j.jssc.2007.01.003; PII: S0022-4596(07)00020-5; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CESIUM COMPOUNDS; CLATHRATES; CUBIC LATTICES; GERMANIUM COMPOUNDS; MONOCRYSTALS; SILVER COMPOUNDS; SODIUM COMPOUNDS; SPACE GROUPS; SYNTHESIS; X-RAY DIFFRACTION

Citation Formats

Beekman, M., Wong-Ng, W., Kaduk, J.A., Shapiro, A., and Nolas, G.S. Synthesis and single-crystal X-ray diffraction studies of new framework substituted type II clathrates, Cs{sub 8}Na{sub 16}Ag{sub x}Ge{sub 136-x} (x<7). United States: N. p., 2007. Web. doi:10.1016/j.jssc.2007.01.003.
Beekman, M., Wong-Ng, W., Kaduk, J.A., Shapiro, A., & Nolas, G.S. Synthesis and single-crystal X-ray diffraction studies of new framework substituted type II clathrates, Cs{sub 8}Na{sub 16}Ag{sub x}Ge{sub 136-x} (x<7). United States. doi:10.1016/j.jssc.2007.01.003.
Beekman, M., Wong-Ng, W., Kaduk, J.A., Shapiro, A., and Nolas, G.S. Thu . "Synthesis and single-crystal X-ray diffraction studies of new framework substituted type II clathrates, Cs{sub 8}Na{sub 16}Ag{sub x}Ge{sub 136-x} (x<7)". United States. doi:10.1016/j.jssc.2007.01.003.
@article{osti_21015749,
title = {Synthesis and single-crystal X-ray diffraction studies of new framework substituted type II clathrates, Cs{sub 8}Na{sub 16}Ag{sub x}Ge{sub 136-x} (x<7)},
author = {Beekman, M. and Wong-Ng, W. and Kaduk, J.A. and Shapiro, A. and Nolas, G.S.},
abstractNote = {New inorganic type II clathrates with Ag atoms substituting for framework Ge atoms, Cs{sub 8}Na{sub 16}Ag{sub x}Ge{sub 136-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 Fd3-barm) with a=15.49262(9)A, 15.51605(6)A, 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.},
doi = {10.1016/j.jssc.2007.01.003},
journal = {Journal of Solid State Chemistry},
number = 3,
volume = 180,
place = {United States},
year = {Thu Mar 15 00:00:00 EDT 2007},
month = {Thu Mar 15 00:00:00 EDT 2007}
}