A high-performance low-sensitivity explosive, LX-11: benefiting from N–NH2 side-arm hydrogen bonding

Abstract

Balancing high energy and low sensitivity has long been a significant concern for high energy density materials (HEDMs). In this work, we report the preparation and properties of a new insensitive high explosive (IHE): 3-nitro-5-(6-nitro-3H-[1,2,4]triazolo[1,5-d]tetrazol-2(5H)-yl)-1H-1,2,4-triazol-1-amine (LX-11). It exhibits a high heat of formation of 3.06 kJ g⁻¹ and a high detonation velocity (D_v) of 9740 m s⁻¹, as well as good thermal stability (T_d(onset) = 201 °C) and insensitive mechanical sensitivity (IS = 40 J, FS > 360 N). The structure ofLX-11 features a novel [1,2,4]triazolo[2,3-d]tetrazole fused-ring framework with high nitrogen content. Furthermore, the introduction of a side-arm N–NH₂, giving rise to an extensive 3D hydrogen bonding network, enhanced performance and stability. The additional side-arm effect gives LX-11 a high density of 1.95 g cm⁻³ with a crystal packing coefficient (PC) of up to 81.9%, and thus a D_v comparative with the powerful military explosive CL-20 but with much lower sensitivity.