New refinement of Ni5.20Sn8.7Zn4.16Cu1.04 and its non-isotypy with Ni2Sn2Zn.
The noncentrosymmetric space group P43m but a pseudocentric cubic crystal structure were reported for the compound Ni5.20Sn8.7Zn4.16Cu1.04 [Larsson et al. (1994). Acta Cryst. C50, 9-12]. The recently described Ni2Sn2Zn shows a closely related structure, although it is centrosymmetric and contains additional voids which are partially occupied. Therefore, a new refinement of Ni5.20Sn8.7Zn4.16Cu1.04 based on the originally published structure factors was performed. The results indicate that the structure can indeed be described in the centrosymmetric space group Pm3m; no justification for the absence of the inversion centre could be found within the accuracy of the available data. In comparison with Ni2Sn2Zn, slight but significant differences were confirmed; consequently, the two structures are topologically related but not isotypic.
Forschungszentrum Jlich, IEK-2, 52425 Jülich, Germany.
Clemens
C
Schmetterer
University of Vienna, Department of Inorganic Chemistry/Materials Chemistry, Waehringer Strasse 42, 1090 Wien, Austria.
Hans
H
Flandorfer
University of Vienna, Institut für Mineralogie und Kristallographie, Althanstrasse 14, 1090 Wien, Austria.
Herta Silvia
HS
Effenberger
Ni5.20Sn8.7Zn4.16Cu1.04; defect structure; rerefinement