The germanides ScTGe (T = Co, Ni, Cu, Ru, Rh, Pd, Ag, Ir, Pt, Au) - Structure and Sc-45 solid state NMR spectroscopy

Abstract

The germanides ScTGe (T = Co, Ni, Cu, Ru, Rh, Pd, Ag, Ir, Pt, Au) were obtained in X-ray pure form by arcmelting of the elements. The structures of the members with T = Co, Ni, Cu, Rh, Pd, Ag, Ir, and Pt were refined on the basis of single crystal X-ray diffractometer data. The germanides with T = Cu, Ru, Pd, Ag crystallize with the hexagonal ZrNiAl type structure, space group P62m and those with T = Co, Ni, Rh, Ir, Pt adopt the orthorhombic TiNiSi type. ScAuGe is isotypic with NdPtSb. All germanides exhibit single scandium sites. A simple systematization of the structure type according to the valence electron concentration is not possible. The Sc-45 solid state NMR parameters (I(night shifts and nuclear electric quadrupole coupling constants) of those members crystallizing in the TiNiSi structure show systematic trends as a function of valence electron concentration number. Furthermore, within each T-group the Knight shift decreases with increasing atomic number; this correlation also includes previously published results on the isotypic suicide family. The Sc-45 quadrupolar interaction tensor components are generally well-reproduced by quantum mechanical electric field gradient calculations using the WIEN2k code. (C) 2014 Elsevier Masson SAS. All rights reserved.