Synthesis and characterization of a new ternary imide-Li 2Ca(NH)2

Abstract

The ternary imide Li2Ca(NH)2 was successfully synthesized by dehydrogenating a mixture of LiNH2 and CaH2 at a molar ratio of 2:1 in a stream of purified argon at 300°C. A powder X-ray diffraction measurement revealed that Li2Ca(NH)2 was of the trigonal anti-La2O3 structure (space group P3m1) with lattice constants of a = 3.5664(3)Å and c = 5.9540(8) Å. Ca occupied the 1b site (0, 0, 1/2), Li occupied the 2d site (1/3, 2/3, 0.8841(22)), and N occupied the 2d site (1/3, 2/3, 0.2565(15)). Nuclear magnetic resonance and X-ray absorption fine structure analyses demonstrated that each Li ion was coordinated with four imide ions and each Ca ion was coordinated with six imide ions. © 2007 American Chemical Society.