We have synthesized the tetragonal modification of LiSr 2 H 2 N and novel LiBa 2 H 2 N in single phase bulk via solid state reaction assisted by ball milling and grown single crystals from alkali metal melts. The crystal structure was determined via powder and single crystal X‐ray diffraction. The obtained structural data reveal that LiSr 2 H 2 N crystallizes in the non‐centrosymmetric space group I 4 mm , rather than in the previously reported centrosymmetric space group I 4/ mmm , resulting in a fully ordered structural model and particularly resolving the site disorder of the nitride ion in the previously discussed structure. We also report the first synthesis and crystal growth of LiBa 2 H 2 N, which crystallizes isostructural with LiSr 2 H 2 N. We discuss structural relations with the reported centrosymmetric tetragonal model and an orthorhombic form earlier reported. Furthermore, we analyze the structure of LiBa 2 H 2 N in comparison to the subnitride LiBa 2 N.
Liang et al. (Fri,) studied this question.