TY - JOUR
T1 - Synthesis and X-ray characterization of silicon clathrates
AU - Ramachandran, Ganesh K.
AU - Dong, Jianjun
AU - Diefenbacher, Jason
AU - Gryko, Jan
AU - Marzke, Robert F.
AU - Sankey, Otto F.
AU - McMillan, Paul F.
N1 - Funding Information:
We are indebted to Professor Michael O’Kee!e for many valuable discussions and his insightful comments. Thanks are also due to Kurt Lienenweber and Michael Shemkunas for useful discussions. It is also our pleasure to thank one of the anonymous reviewers whose comments and suggestions helped shape the "nal form of this manuscript. This work was supported by NSF MRSEC award DMR 96-32635 and NSF award EAR 93-05425. A Jacksonville State University Faculty Research grant also supported one of us (J.G.).
PY - 1999/7
Y1 - 1999/7
N2 - We report on the synthesis and characterization of two silicon clathrates, Na8Si46 and NaxSi136(x = 4-23), by powder X-ray diffraction, combined with Rietveld profile analysis. In Na8Si46, no deviation from the ideal stoichiometry is observed. In NaxSi136, systematic changes in X-ray diffraction intensities enable the Na content and site occupancy to be characterized. In the same structure, we observe a ∼0.5% increase in the unit cell edge upon progressing from Na4Si136 to Na23Si136. A statistical mechanical model, combined with experimental data for this phase reveals a preference for the removal of sodium from the smaller of the two available cages by 0.190 ± 0.050 eV.
AB - We report on the synthesis and characterization of two silicon clathrates, Na8Si46 and NaxSi136(x = 4-23), by powder X-ray diffraction, combined with Rietveld profile analysis. In Na8Si46, no deviation from the ideal stoichiometry is observed. In NaxSi136, systematic changes in X-ray diffraction intensities enable the Na content and site occupancy to be characterized. In the same structure, we observe a ∼0.5% increase in the unit cell edge upon progressing from Na4Si136 to Na23Si136. A statistical mechanical model, combined with experimental data for this phase reveals a preference for the removal of sodium from the smaller of the two available cages by 0.190 ± 0.050 eV.
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U2 - 10.1006/jssc.1999.8295
DO - 10.1006/jssc.1999.8295
M3 - Article
AN - SCOPUS:0000856561
SN - 0022-4596
VL - 145
SP - 716
EP - 730
JO - Journal of Solid State Chemistry
JF - Journal of Solid State Chemistry
IS - 2
ER -