The phase stability of predicted pentazole derivate compounds under high pressure.

Pentazole as one typical extreme explosive has been applied in the synthesis of a metal pentazole complex under extremely-high pressure and low temperature. In order to evaluate the stabilities and detonation performances of pentazole complexes in possible applications, we predict four pentazole derivate molecules and crystals (dipentazole, octaazapentalene, azidopentazole and tripentazolamine) based on DFT and Monte-Carlo methods, wherein both crystalline octaazapentalene and tripentazolamine display remarkable dynamic stabilities and excellent denotation properties. To understand the relationship between the structures and gradually increased pressure, all the predicted crystal structures are studied under gradually increased pressure from ambient pressure to 200 Gpa. In response to extremely high pressures, the stability of the energetic crystals is dominated by molecular compressibility under limit states, where the bond cleavage results in structural dissociation under high pressure. However, low molecular planarization energy generally corresponds to a pressure-induced phase transition of pentazolate crystals.