Synthesis of AgN5 and its extended 3D energetic framework

Abstract

The pentazolate anion, as a polynitrogen species, holds great promise as a high-energy density material for explosive or propulsion applications. Designing pentazole complexes that contain minimal non-energetic components is desirable in order to increase the material’s energy density. Here, we report a solvent-free pentazolate complex, AgN5, and a 3D energetic-framework, [Ag(NH3)2]+[Ag3(N5)4]ˉ, constructed from silver and cyclo-N5ˉ. The complexes are stable up to 90 °C and only Ag and N2 are observed as the final decomposition products. Efforts to isolate pure AgN5 were unsuccessful due to partial photolytical and/or thermal-decomposition to AgN3. Convincing evidence for the formation of AgN5 as the original reaction product is presented. The isolation of a cyclo-N5ˉ complex, devoid of stabilizing molecules and ions, such as H2O, H3O+, and NH4+, constitutes a major advance in pentazole chemistry.

Novel All‐Nitrogen Molecular Crystals of Aromatic N10

“…This is much higher than those typical energetic materials, such as TATB, RDX, and HMX, which have energy densities around 1–3 kJ g −1 . [ 30 ] In addition, due to the instability of a single cyclic N 5 ring, nonenergetic ions are required to stabilize them in the complexes in previous works, [ 9–12,31,32 ] which reduces the energy density of the materials. In our predicted three polynitrogen crystals, the covalent bond between the two cyclic N 5 rings naturally stabilize each other and thus form stable bispentazole molecular crystals even at ambient pressure.…”

What Makes an Explosion Happen?

“…This configuration clarifies the reason why the acidic entrapment could stabilize the cyclo-N5ˉ[25][26][27][28][29] and why the X:H-Y and X::Y or HH coexistence is essential to the constrained explosion. The X:H breaking initiates and the X::X fosters the explosion of the cyclo-N5complexes.…”

High‐Pressure Synthesis of Metal–Inorganic Frameworks Hf4N20⋅N2, WN8⋅N2, and Os5N28⋅3 N2 with Polymeric Nitrogen Linkers

“…So, the first successful synthesis of alkali metal pentazolates (salts containing cyclo ‐N 5 − anions) was performed at high pressure . Later, unsubstituted cyclo ‐N 5 − was stabilized at ambient conditions too . Metal–pentazolate frameworks (AgN 5 , Cu(N 5 )(N 3 ), Na 24 N 60 , Na 20 N 60 ) might not only have applications as energetic materials, but also be intrinsically interesting as direct inorganic structural analogues of azolate metal–organic frameworks and framework materials based on an aromatic inorganic linker .…”