The stannides ScNi 1.54(1)Sn and ScNi 1.85(1)Sn – Structures, 45Sc NMR and 119Sn Mössbauer spectroscopy

Abstract

The stannides ScNi 1.54(1)Sn and ScNi 1.85(1)Sn were prepared from the elements by arc-melting. Single crystals were investigated on the basis of X-ray diffractometer data: MnCu 2Al type (Heusler structure), F m 3 ¯ m , a = 618.5(1), wR2 = 0.0110, 44 F 2 values, 6 variables for ScNi 1.54Sn and a = 621.4(2), wR2 = 0.0242, 46 F 2 values, 6 variables for ScNi 1.85Sn. The scandium and tin atoms build up a rocksalt type substructure in which the tetrahedral voids are partially occupied. This way the scandium and tin atoms both have cubic nickel coordination. Both samples have been studied by 119Sn Mössbauer and 45Sc solid state NMR, revealing single tin and scandium sites, in agreement with the crystal structures. The spectroscopic data also account for the different defect formation.