Proposal Summary: This is a study to determine the exact form of the complex between hydrazine (N2H4) and oxalic acid (C2H4O2) at room temperature, and also the perdeuterated complex at both room temperature and at low temperature (there is a solid-state phase transition at ~250K, whereby the c-cell dimension of the room temperature cell doubles). We request beamtime on SXD to be able to investigate these structures and to find out exactly what the structures are, and which are the proper space groups. Also, we would like to understand what happens when the phase transition occurs at ~250K.