Zintl-Phase Sr3LiAs2H: Crystal Structure and Chemical Bonding Analysis by the Electron Localizability Approach

摘要

The compound Sr3LiAs2H was synthesized by reaction of elemental strontium, lithium, and arsenic, as well as LiH as hydrogen source. The crystal structure was determined by single-crystal X-ray diffraction: space group Pnma; Pearson symbol oP28; a = 12.0340(7), b = 4.4698(2), c = 12.5907(5) angstrom; V = 677.2(1) angstrom(3); R-F = 0.047 for 1021 reflections and with 36 parameters refined. The positions of the hydrogen atoms were first revealed by the electron localizability indicator and subsequently confirmed by crystal structure refinement. In the crystal structure of Sr3LiAs2H the metal atoms are arranged in a Gd3NiSi2-type motif, whereas the hydrogen atoms are arranged in a distorted tetrahedral environment formed by strontium. The calculated band structure revealed that Sr3LiAs2H is a semiconductor, which is in agreement with its diamagnetic behavior. Thus, Sr3LiAs2H is considered as a (charge-balanced) Zintl phase.