Multinuclear solid state NMR spectroscopy of ternary rare-earth silicides RET ₂Si₂ and germanides LaT ₂Ge₂ (RE = Sc, Y, La, Lu; T = Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Os, Ir, Pt, Au)

A series of ternary rare earth – transition metal – tetrelides RET 2 Tt 2 ( RE = Sc, Y, La, Lu; T = Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Os, Ir, Pt, Au; Tt = Si, Ge) was synthesized by arc melting of the elements and subsequent annealing. The samples were characterized by powder X-ray diffraction and in addition, the structures of RE Os 2 Si 2 ( RE = Y, La, Lu), LaAu 2 Si 2 , LaAg 2 Ge 2 and LaAu 2 Ge 2 were refined from single crystal X-ray diffractometer data. The tetrelides crystallize with the ThCr 2 Si 2 type ( I 4/ mmm ) except the platinum compounds which adopt the klassengleiche superstructure of the CaBe 2 Ge 2 type ( P 4/ nmm ). The transition metal atoms have tetrahedral tetrel coordination and the tetrahedra condense to layers via common edges. The stacking of these layers leads to Tt − Tt bonds in the ThCr 2 Si 2 type phases and heteroatomic T − Tt bonds in the CaBe 2 Ge 2 type phases. The rare earth atoms fill larger cages within these three-dimensional networks (coordination number 16 with RE @ T 8 Tt 8 ) with site symmetries 4/ mmm (ThCr 2 Si 2 type) and 4 mm (CaBe 2 Ge 2 type). Systematic multinuclear solid state NMR spectroscopic investigations allowed observing the effect of the involved rare-earth metal, transition metal and tetrel group element, respectively. In particular, 29 Si isotropic resonance shifts can be predicted from element-specific increments and interatomic Si–Si bonding interactions manifest themselves in axially symmetric magnetic shielding anisotropies.