Metal-N-H systems have recently attracted considerable attention as alternative hydrogen storage materials to traditional metal hydrides. In this work, the reactions of the mixture LiNH2-MgH2 (1:1) during different mechanical milling processes and the subsequent dehydrogenation reaction were investigated by using TGA, XRD and FT-IR in order to determine an optimal condition for the formation of pure LiMgN. High-energy milling (SPEX mill) and low-energy milling (rolling jar) techniques were used in this work. The results demonstrated that monolithic LiMgN can be produced using the low-energy ball milling technique. The hydrogenation properties of the as-prepared LiMgN were investigated by a Sieverts' type instrument. In contrast, multiple reactions including the metathesis reaction between LiNH2 and MgH2 and release of H-2 and/or NH3 took place during high-energy milling using the SPEX mill, which resulted in complicated and unexpected reactions during the subsequent dehydrogenation experiments. Consequently. the dehydrogenated products from the high-energy milled samples consisted of multi-phase mixtures. (C) 2009 Elsevier B.V. All rights reserved.