Hexanitrohexaazaadamantane: A New Potential High-Energy-Density Compound Superior to Hexanitrohexaazaisowurtzitane (CL-20)

To look for new high-energy-density compounds (HEDC) with good performance, molecular mechanics (MM) was first employed to predict the molecular spatial packings (or crystal structures) of hexanitrohexaazaadamantane (HNHAA) and the well-known high-energy-density compound hexanitrohexaazawurtzitane (epsilon-CL-20). Then, periodic ab initio calculations, using the GGA-RPBE method, were carried out on the band structures of the two predicted crystals. The results showed that they tended to crystallize in the same space group P21/c, and they have similar density of states (DOS) and comparable band gaps (E, 3.546 and 3.522eV for HNHAA and epsilon-CL-20, respectively), which presented similar thermal initiation mechanisms and comparable sensitivity. Furthermore, HNHAA was recommended as a new potential HEDC with better detonation properties than the well-known epsilon-CL-20, due to its larger density (2.315g center dot cm-3) than epsilon-CL-20 (2.173g center dot cm-3).