This article describes in situ heating and observation of a LiNH2-2LiH mixture in an environmental scanning electron microscope (ESEM). The LiNH2-2LiH mixture showed extensive morphological changes with heating and attendant hydrogen desorption. Static images and real-time movies were obtained during the dehydrogenation process. H-2 evolution commences at similar to 150 degrees C (LiNH2 + 2LiH -> Li2NH + H-2 + LiH), and continues until similar to 410 degrees C. Dramatic morphological changes are observed at 220 and 410 degrees C (Li2NH + LiH -> Li3N + H-2). The material converts to a microcrystalline phase at higher temperatures (>500 degrees C). The observed H-2 desorption and morphological changes occur at temperatures in good agreement with those measured by complementary analytical methods. This is the first time the major structural and morphological changes attendant on H-2 loss from this system have been observed in situ and in real time. (C) 2008 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.