The aims of this proposal are to explore the high-pressure, high-temperature behaviour of 3 important energetic materials - FOX-7, CL-20, and ADN. These experiments are expected to identify and structurally characterise new forms of these materials, and offer the potential for the recovery of metastable forms to ambient conditions. These recovered forms may exhibit enhanced properties such as reduced sensitivity or higher density. The studies will also provide equations of state for these materials. Phase transitions observed under these extreme conditions also have important implications for the modelling of the performance characteristics of these materials.