Hydrogenation Reaction Pathway in Li2Mg(NH)2

Results of the first time-resolved in situ neutron diffraction measurements during absorption of deuterium in Li2Mg(ND)2 reveal the occurrence of a two-stage reaction. The first stage involves the reaction to LiND2, LiD, and Li2Mg2(ND)3, with the second stage leading to full deuteration to Mg(ND2)2 and LiD. Since no structural model for Li2Mg2(NH)3 exists in the literature, its structure has been determined from refinement of X-ray and neutron diffraction data. These new data provide key information toward the clarification of the hydrogenation mechanism in this system.