Nd3NCl6 und Nd4NS3Cl3: Zwei Neodymnitrid‐Derivate mit diskreten Einheiten kantenverknüpfter ([N2Nd6]12+) bzw. isolierter [NNd4]9+‐Tetraeder

Nd₃NCl₆ and Nd₄NS₃Cl₃: Two Derivatives of Neodymium Nitride with Discrete Units of Edge‐Shared (N₂Nd₆]¹²⁺) and Isolated NNd₄]⁹⁺ Tetrahedra, respectively For the preparation of Nd₃NCl₆ (orthorhombic, Pbca; a = 1049.71(8), b = 1106.83(8), c = 1621.1(1) pm; Z = 8) and Nd₄NS₃Cl₃ (hexagonal, P6₃mc; a = 922.78(6), c = 683.06(4) pm; Z = 2) elemental neodymium is reacted with sodium azide (NaN₃), neodymium trichloride (NdCl₃) and in the case of Nd₄NS₃Cl₃ additionally with sulfur in evacuated silica tubes at 750 °C (Nd₃NCl₆) and 850 °C (Nd₄NS₃Cl₃), respectively. Thereby the hydrolysis‐sensitive nitride chloride forms coarse, brick‐shaped single crystals, while those of the insensitive nitride sulfide chloride emerge hexagonally and pillar‐shaped. The pale violet compounds each exhibit NNd₄] tetrahedra as characteristic structural features, which are connected via a common edge to form discrete pairs of tetrahedra (N₂Nd₆]¹²⁺) in Nd₃NCl₆ and are present in Nd₄NS₃Cl₃ even as isolated NNd₄]⁹⁺ units. Their three‐dimensional cross‐linkage as well as the charge‐balance regulation proceed solely through Cl^– anions in the nitride chloride, but through equimolar amounts of S^2– and Cl^– anions in the nitride sulfide chloride. The crystal structure of Nd₃NCl₆ shows three crystallographically independent Nd³⁺ cations, each of which is eightfold coordinated by anions (Nd1: 2 N^3– + 6 Cl^–; Nd2 and Nd3: 1 N^3– + 7 Cl^–). Only two different kinds of Nd³⁺ underlie the structure of Nd₄NS₃Cl₃: Nd1 is surrounded by one N^3–, six S^2– and three Cl^– with CN = 10, whereas one N^3–, four S^2– and three Cl^– only are coordinating Nd2 with CN = 8.