M 4 N 2 Te 3 (M = La – Nd): Die ersten Nitridtelluride der dreiwertigen Lanthanide

M 4 N 2 Te 3 (M = La – Nd): The First Nitride Tellurides with Trivalent Lanthanides The oxidation of the light lanthanides (M = La – Nd) with tellurium and sodium azide (NaN 3 ) in the presence of the corresponding trichlorides (MCl 3 ) yields the first nitride tellurides of the lanthanides with the composition M 4 N 2 Te 3 when appropriate molar ratios of the reactants are used. Additional sodium chloride (NaCl) as a flux secures complete and fast reactions (7 d) at 900 °C in evacuated silica tubes as well as the formation of black single crystals. The orthorhombic crystal structure (Pnma, Z = 4) was determined from single crystal X‐ray diffraction data for La 4 N 2 Te 3 (a = 746.58(6), b = 1184.16(9), c = 1160.71(9) pm), Ce 4 N 2 Te 3 (a = 739.26(6), b = 1169.73(9), c = 1148.04(9) pm), Pr 4 N 2 Te 3 (a = 734.75(6), b = 1163.82(9), c = 1139.53(9) pm), and Nd 4 N 2 Te 3 (a = 730.61(6), b = 1159.57(9), c = 1131.46(9) pm). Three crystallographically different M 3+ cations are present, two of them (M1 and M2) reside in sixfold coordination of two N 3− and four Te 2− anions forming trigonal prisms. The third cation (M3) is coordinated by two N 3− and five Te 2− in the shape of a monocapped trigonal prism. However, the main feature of the crystal structure comprises N 3− ‐centred (M 3+ ) 4 tetrahedra which are connected via trans ‐edges to build up one‐dimensional infinite chains   ∞ 1 {[NM   4/2 e ] 3+ } (e = edge‐sharing). These chains, caused by a significant tilting of the single tetrahedra relative to each other, are not stretched to ideal linearity, so a doubled repetition period compared to the single one (≈ two edge lengths of a tetrahedron) is necessary. They get bundled along [010] like a hexagonal rod packing and held together by two crystallographically different Te 2− anions. Further motifs for the interconnection of [NM 4 ] 9+ tetrahedra in crystal structures of nitride chalcogenides and halides of the rare‐earth elements (M = Sc, Y, La; Ce – Lu) with ratios of N : M = 1 : 2 are presented and discussed for comparison.