Unleashing Ultrahigh Detonation Performance with Oxalyldihydrazinium Dication-Based Energetic Salts

Abstract

A new series of high energy density materials were synthesized by combining the oxalyldihydrazinium (H₂ODH²⁺) dication with 5,5′-tetranitro-2,2′-bi-1H-imidazolate (TNBI^2–), 5,5′-diamino-4,4′-dinitramino-3,3′-bi-1,2,4-triazolate (ANAT^2–) and bis[3-(5-nitroimino-1,2,4-triazolate)] (BNT^2–) dianions. These materials were fully characterized by nuclear magnetic resonance (¹H and ¹³C) and infrared spectroscopy, gas pycnometry, thermogravimetric analysis and differential scanning calorimetry. In addition, the crystal structures of the energetic salts [H₂ODH][TNBI] and [H₂ODH][ANAT] were determined by single-crystal X-ray diffraction. Thermal analysis revealed decomposition temperatures of 183 °C for [H₂ODH][ANAT], 200 °C for [H₂ODH][TNBI] and 209 °C for [H₂ODH][BNT], while the densities of these salts were determined to be 1.82, 1.91, and 1.94 g cm^–3, respectively. The structural features of these new energetic salts revealed π-stacking and hydrogen-bonding interactions, which contribute to the close packing and associated high densities. All salts exhibited high detonation properties (detonation pressure: 39.2–43.7 GPa; detonation velocity: 9246–9783 m s^–1), which are superior or similar to those of benchmark explosives such as 1,3,5-trinitroperhydro-1,3,5-triazine (RDX) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX).