Darstellung und Kristallstruktur des Lithium‐Strontium‐Hydridnitrids LiSr 2 H 2 N

Synthesis and Crystal Structure of the Lithium Strontium Hydride Nitride LiSr 2 H 2 N LiSr 2 H 2 N was synthesized by the reaction of LiH and Li 3 N with elemental strontium in sealed tantalum tubes at 650 °C within seven days. This second example of a quaternary hydride nitride crystallizes orthorhombically in space group Pnma (no. 62) with the lattice constants a = 747.14(5) pm, b = 370.28(3) pm and c = 1329.86(9) pm (Z = 4). Its crystal structure contains both kinds of anions H − and N 3− in a sixfold distorted octahedral metal cation coordination each. The coordination polyhedra [(H1)Sr 5 Li] 10+ , trans ‐[(H2)Sr 4 Li 2 ] 9+ and [NSr 5 Li] 8+ are connected via edges and corners to form a three‐dimensional network. Two crystallographically different Sr 2+ cations exhibit a sevenfold monocapped trigonal prismatic coordination by H − and N 3− with [(Sr1)H 5 N 2 ] 9− and [(Sr2)H 4 N 3 ] 11− polyhedra, wheras Li + shows a nearly planar fourfold coordinative environment ([LiH 3 N] 5− ). Cationic double chains of edge‐shared [NSr 5 Li] 8+ octahedra dominate the structure according to $^{1}_{\infty}\rm \{[N(Sr1)_{2/2}(Sr2)_{3/3}Li_{1/1}]^{2+}\}$ . Running parallel to the [0 1 0] direction, they are bundled like a hexagonal rod‐packing which is interconnected by H − anions within the (0 0 1) plane first and finally even in the third dimension ( i. e . along [0 0 1]). Therefore the structure of LiSr 2 H 2 N is compared to that one of the closely related quaternary hydride oxide LiLa 2 HO 3 .