New refinement of Ni5.20Sn8.7Zn4.16Cu1.04 and its non‐isotypy with Ni2Sn2Zn

The noncentrosymmetric space group P3m but a pseudocentric cubic crystal structure were reported for the compound Ni_5.20Sn_8.7Zn_4.16Cu_1.04 Larsson et al. (1994). Acta Cryst. C 50 , 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 Ni_5.20Sn_8.7Zn_4.16Cu_1.04 based on the originally published structure factors was performed. The results indicate that the structure can indeed be described in the centrosymmetric space group Pmm; 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.