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Cu3Sn - understanding the systematic absences.

Müller, Carola LU and Lidin, Sven LU (2014) In Acta Crystallographica. Section B: Structural Science, Crystal Engineering and Materials 70(Pt 5). p.879-887
Abstract
The intermetallic compound Cu3Sn has previously been described as a long-period antiphase boundary superstructure of the Cu3Ti structure type. While the compound itself has been reported as a tenfold and an eightfold superstructure, ternary doped alloys show shorter repetitions. Interestingly, the diffraction patterns of these compounds show non-crystallographic absences that cannot be explained using the superstructure models. Since the compound exhibits phase broadening, these models are not satisfactory because the paucity of observed data does not allow for a refinement of the composition. Here, an alternative, superspace model in the orthorhombic space group Xmcm(0β0)000 is proposed, with the centering vectors (0,0,0,0) and (½,0,0,½).... (More)
The intermetallic compound Cu3Sn has previously been described as a long-period antiphase boundary superstructure of the Cu3Ti structure type. While the compound itself has been reported as a tenfold and an eightfold superstructure, ternary doped alloys show shorter repetitions. Interestingly, the diffraction patterns of these compounds show non-crystallographic absences that cannot be explained using the superstructure models. Since the compound exhibits phase broadening, these models are not satisfactory because the paucity of observed data does not allow for a refinement of the composition. Here, an alternative, superspace model in the orthorhombic space group Xmcm(0β0)000 is proposed, with the centering vectors (0,0,0,0) and (½,0,0,½). The presence of the non-crystallographic absences is explained as a result of a dominating occupational modulation that is accompanied by a weaker displacive modulation. In consistency with the EDXS results, the composition has been refined to Cu3 + xSn from single-crystal X-ray diffraction data. It is further demonstrated that by varying the length and the direction of the modulation wavevector in the superspace model, the ternary Cu3Sn compounds and other colored hexagonal close packing (h.c.p.) structures can be produced. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Acta Crystallographica. Section B: Structural Science, Crystal Engineering and Materials
volume
70
issue
Pt 5
pages
879 - 887
publisher
Wiley-Blackwell
external identifiers
  • pmid:25274522
  • wos:000342908300013
  • scopus:84907740280
ISSN
2052-5206
DOI
10.1107/S205252061401806X
language
English
LU publication?
yes
id
38d5c4a8-dd76-4427-88d9-fe84bef5cfa1 (old id 4738553)
date added to LUP
2014-11-17 11:33:15
date last changed
2017-01-01 03:43:04
@article{38d5c4a8-dd76-4427-88d9-fe84bef5cfa1,
  abstract     = {The intermetallic compound Cu3Sn has previously been described as a long-period antiphase boundary superstructure of the Cu3Ti structure type. While the compound itself has been reported as a tenfold and an eightfold superstructure, ternary doped alloys show shorter repetitions. Interestingly, the diffraction patterns of these compounds show non-crystallographic absences that cannot be explained using the superstructure models. Since the compound exhibits phase broadening, these models are not satisfactory because the paucity of observed data does not allow for a refinement of the composition. Here, an alternative, superspace model in the orthorhombic space group Xmcm(0β0)000 is proposed, with the centering vectors (0,0,0,0) and (½,0,0,½). The presence of the non-crystallographic absences is explained as a result of a dominating occupational modulation that is accompanied by a weaker displacive modulation. In consistency with the EDXS results, the composition has been refined to Cu3 + xSn from single-crystal X-ray diffraction data. It is further demonstrated that by varying the length and the direction of the modulation wavevector in the superspace model, the ternary Cu3Sn compounds and other colored hexagonal close packing (h.c.p.) structures can be produced.},
  author       = {Müller, Carola and Lidin, Sven},
  issn         = {2052-5206},
  language     = {eng},
  number       = {Pt 5},
  pages        = {879--887},
  publisher    = {Wiley-Blackwell},
  series       = {	Acta Crystallographica. Section B: Structural Science, Crystal Engineering and Materials },
  title        = {Cu3Sn - understanding the systematic absences.},
  url          = {http://dx.doi.org/10.1107/S205252061401806X},
  volume       = {70},
  year         = {2014},
}