BaRu3Sn6 - A tin-rich stannide with Ba@Sn8 and Ru@Sn7 building units

Schwickert C., Pöttgen R.

Zusammenfassung

BaRh3Sn6 has been prepared by melting of the elements in a sealed tantalum tube and subsequent annealing. It crystallizes in the BaRh3Pb6-type structure: Cmcm, a = 807.4(2), b = 2615.3(6), c = 444.0(1) pm, wR = 0.0535, 957 F2 values, 36 variables. The structure is composed of Ba@Sn8 trapezoids (349 and 353 pm Ba-Sn) and Ru@Sn7 units (255- 284 pm Ru-Sn) which can be derived from an octahedron by replacement of one apex by a pair of tin atoms. The Ru@Sn 7 units are condensed to strands via the trapezoidal faces, and these strands are connected to the Ba@Sn8 trapezoids via common edges. The tin substructure of BaRu3Sn6 exhibits a broad range of Sn-Sn distances (310 - 354 pm). © 2014 Verlag der Zeitschrift für Naturforschung, Tübingen.