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Title: Superspace-group approach to the phase transition of Cu[sub 8]GeSe[sub 6]

Abstract

The high- and low-temperature forms, i.e., phase I (stable above 328 K) and phase II (stable below 328 K), of Cu[sub 8]GeSe[sub 6] have been investigated by the powder X-ray diffraction method. Cu[sub 8]GeSe[sub 6] II is hexagonal with A = 12.6438(2), C = 11.7570(1) [angstrom], Z = 6, and P6[sub 3]cm, and its structure is considered to be a superstructure of the high-temperature form, Cu[sub 8]GeSe[sub 6] I (hexagonal, a = 7.3164(4) [approx equal] A/[radical]3, c = 11.7679(7) [angstrom], Z = 2, and P6[sub 3]mc). Rietveld analysis of Cu[sub 8]GeSe[sub 6] I (350 K) and II (290 K) has been performed using diffraction data measured by a high-resolution powder diffractometer and synchrotron X-ray radiation. For Cu[sub 8]GeSe[sub 6] II, a four-dimensional superspace group for commensurate modulation, P6[sub 3]mc (1/3 1/3 0), with basic cell constants a = 7.2999, c = 11.7570 [angstrom] has been successfully applied (R[sub wp] = 0.054). The superspace-group description allows uniform treatment of both forms, and the phase transition of Cu[sub 8]GeSe[sub 6] is explained in terms of the presence and absence of commensurate modulation waves.

Authors:
; ; ;  [1]; ;  [2]
  1. (National Inst. for Research in Inorganic Materials, Namiki, Tsukuba (Japan))
  2. (Univ. of Lausanne (Switzerland). Inst. of Crystallography)
Publication Date:
OSTI Identifier:
6103655
Resource Type:
Journal Article
Journal Name:
Journal of Solid State Chemistry
Additional Journal Information:
Journal Volume: 146:2; Journal ID: ISSN 0022-4596
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CALORIMETRY; COPPER SELENIDES; CRYSTAL STRUCTURE; EXPERIMENTAL DATA; GERMANIUM SELENIDES; LATTICE PARAMETERS; PHASE STUDIES; TEMPERATURE DEPENDENCE; X-RAY DIFFRACTION; CHALCOGENIDES; COHERENT SCATTERING; COPPER COMPOUNDS; DATA; DIFFRACTION; GERMANIUM COMPOUNDS; INFORMATION; NUMERICAL DATA; SCATTERING; SELENIDES; SELENIUM COMPOUNDS; TRANSITION ELEMENT COMPOUNDS; 360602* - Other Materials- Structure & Phase Studies

Citation Formats

Onoda, Mitsuko, Ishii, Motohiko, Shibata, Kenji, Yamamoto, Akiji, Pattison, P., and Chapuis, G. Superspace-group approach to the phase transition of Cu[sub 8]GeSe[sub 6]. United States: N. p., 1999. Web. doi:10.1006/jssc.1999.8362.
Onoda, Mitsuko, Ishii, Motohiko, Shibata, Kenji, Yamamoto, Akiji, Pattison, P., & Chapuis, G. Superspace-group approach to the phase transition of Cu[sub 8]GeSe[sub 6]. United States. doi:10.1006/jssc.1999.8362.
Onoda, Mitsuko, Ishii, Motohiko, Shibata, Kenji, Yamamoto, Akiji, Pattison, P., and Chapuis, G. Wed . "Superspace-group approach to the phase transition of Cu[sub 8]GeSe[sub 6]". United States. doi:10.1006/jssc.1999.8362.
@article{osti_6103655,
title = {Superspace-group approach to the phase transition of Cu[sub 8]GeSe[sub 6]},
author = {Onoda, Mitsuko and Ishii, Motohiko and Shibata, Kenji and Yamamoto, Akiji and Pattison, P. and Chapuis, G.},
abstractNote = {The high- and low-temperature forms, i.e., phase I (stable above 328 K) and phase II (stable below 328 K), of Cu[sub 8]GeSe[sub 6] have been investigated by the powder X-ray diffraction method. Cu[sub 8]GeSe[sub 6] II is hexagonal with A = 12.6438(2), C = 11.7570(1) [angstrom], Z = 6, and P6[sub 3]cm, and its structure is considered to be a superstructure of the high-temperature form, Cu[sub 8]GeSe[sub 6] I (hexagonal, a = 7.3164(4) [approx equal] A/[radical]3, c = 11.7679(7) [angstrom], Z = 2, and P6[sub 3]mc). Rietveld analysis of Cu[sub 8]GeSe[sub 6] I (350 K) and II (290 K) has been performed using diffraction data measured by a high-resolution powder diffractometer and synchrotron X-ray radiation. For Cu[sub 8]GeSe[sub 6] II, a four-dimensional superspace group for commensurate modulation, P6[sub 3]mc (1/3 1/3 0), with basic cell constants a = 7.2999, c = 11.7570 [angstrom] has been successfully applied (R[sub wp] = 0.054). The superspace-group description allows uniform treatment of both forms, and the phase transition of Cu[sub 8]GeSe[sub 6] is explained in terms of the presence and absence of commensurate modulation waves.},
doi = {10.1006/jssc.1999.8362},
journal = {Journal of Solid State Chemistry},
issn = {0022-4596},
number = ,
volume = 146:2,
place = {United States},
year = {1999},
month = {9}
}