Darstellung und Kristallstruktur des Lithium‐Strontium‐Hydridnitrids LiSr2H2N

Abstract

AbstractSynthesis and Crystal Structure of the Lithium Strontium Hydride Nitride LiSr2H2NLiSr2H2N was synthesized by the reaction of LiH and Li3N 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 N3− in a sixfold distorted octahedral metal cation coordination each. The coordination polyhedra [(H1)Sr5Li]10+, trans‐[(H2)Sr4Li2]9+ and [NSr5Li]8+ are connected via edges and corners to form a three‐dimensional network. Two crystallographically different Sr2+ cations exhibit a sevenfold monocapped trigonal prismatic coordination by H− and N3− with [(Sr1)H5N2]9− and [(Sr2)H4N3]11− polyhedra, wheras Li+ shows a nearly planar fourfold coordinative environment ([LiH3N]5−). Cationic double chains of edge‐shared [NSr5Li]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 LiSr2H2N is compared to that one of the closely related quaternary hydride oxide LiLa2HO3.