Group 1 amides of general formula MNH2 are some of the most promising materials for hydrogen storage applications due to their relatively low temperatures of hydrogen evolution and ease of rehydrogenation. The first member of this series, LiNH2, has been much studied due to its relatively facile hydrogen absorption and desorption properties, which have their origin in the ease of transformation between the amide and imide (Li2NH) forms. The sodium analogue, NaNH2, is relatively unknown due to its lower hydrogen density and the lack of an imide decomposition product.Recent work by the applicants has identified an unknown phase that appears during the decomposition of NaNH2. that does not correspond to any of the know phases composed from Na, N or H. Temperature programmed decomposition and mass spectroscopy suggest this phase may be sodium imide.