Investigations on the solid state interaction between LiAlH4 and NaNH2

In this paper, two LiAlH4–NaNH2 samples with LiAlH4 to NaNH2 molar ratio of 1/2 and 2/1 were investigated, respectively. It was observed that both samples evolved 2 equiv H2 in the ball milling process, however, the reaction pathways were different. For the LiAlH4–NaNH2 (1/2) sample, Li3Na(NH2)4 and NaAlH4 were formed through cation exchange between reactants. The NaAlH4 formed further reacts with Li3Na(NH2)4 and NaNH2 to give H2, NaH and LiAlN2H2. For the LiAlH4–NaNH2 (2/1) sample, Li3Na(NH2)4, LiNH2 and NaAlH4 were formed firstly through the same cation exchange process. The resulting LiNH2 reacts with the remaining LiAlH4 and produces H2 and Li2AlNH2.