Barium(II)-based molecular perovskite energetic compounds for next-generation pyrotechnic materials

The traditional pyrotechnic compositions formed by mechanically mixing flammable and oxidative agents face problems in complex formulations, inaccurate chemical stoichiometry, and inefficient colour-producing reactions. The emerging molecular perovskite energetic materials embedding ternary ions have evolved into a new platform for developing explosives, propellants, ignitions, and energetic biocides, by taking advantages of easy preparation and high adjustability, nevertheless their potentials in pyrotechnic applications have not been investigated yet. Herein, by assembling barium(II) perchlorate with imidazolium (Him+) and quinuclidinium (Hqe+), respectively, we obtained two new energetic compounds, (Him)(Ba)(ClO4)3 (IBP) in cubic perovskite structure and (Hqe)2(Ba)(ClO4)4 (QBP) in layered perovskite structure. Both IBP and QBP have decomposition peak temperatures exceeding 290 °C and much higher moisture stabilities than barium perchlorate. With the layered structure, QBP has significantly reduced friction sensitivity (144 N) than IBP (5 N). Moreover, the tightly stacking of barium(II), oxidative perchlorate ions, and carbon-rich fuel components at molecular level endows QBP with a high-efficiency and stable combustion outputting a maximum combustion pressure up to 550 kPa, a maximum pressure pulse rate up to 10.48 MPa/s, and a bright green flame. These findings well demonstrated that molecular perovskite energetic compounds integrating luminescent component, oxidative anions, and organic cations are promising contenders for next-generation pyrotechnic materials.