Deflagration or detonation: A new way to evaluate initial thermal decomposition behaviors of energetic complex

Primary explosives generally play a critical role in initiating explosive reactions in energetic systems, where thermal initiation is governed by the stability of structural hot-spot bonds. However, the subsequent deflagration pathway following the thermal initiation has been always overlooked. Some explosives with weak hot-spot bond strength, nonetheless, undergo a stable deflagration process until detonation occurs, indicating the strength of hot-spot bond is insufficient to evaluate the performance prior to detonation. Here, based on the recently synthesized crystalline [Cu(1-MTZ) 4 (ClO 3 ) 2 ], we construct 1-methyltetrazole (1-MTZ) metal complexes [M(1-MTZ) 4 (ClO 3 ) 2 ] (M = Mn 2+ , Fe 2+ , Co 2+ , Ni 2+ , Cu 2+ , and Zn 2+ ) to investigate the role of center metal in both the thermal initiation and the following deflagration process. Density functional theory (DFT) and Car−Parrinello molecular dynamics (CPMD) methods are applied to establish the relationship between the coordinative bond strength/metal stabilization energy and initial dynamic performances. This study reveals that the initial decomposition stage should encompass both the initiation process and the pre-detonation deflagration process, with both processes being regulated by the characteristics of different transition metal centers. Instead of relying on a one-dimensional evaluation approach focused solely on "hot-spot" sites, this study establishes a novel framework for assessing the stability of the entire initial decomposition process.