Kinetic Stability of Pentazole

Abstract

The utility of high energy density materials (HEDMs) comes from their thermodynamic properties which arise from specific structural features that contribute to energy storage. Studies of such structural features seek to increase our understanding of these energy storage mechanisms in order to further enhance their properties. High-nitrogen-containing HEDMs are of particular interest because they are less toxic than traditional HEDMs. Pentazole is the largest of the nitrogen rings which has been synthesized and considered for an HEDM; however, few experimental studies exist due to the difficulty involved in the synthesis, and most previous theoretical studies employed composite methods where lower level geometries were used with higher level methods. Here, the decomposition reaction of pentazole is studied. Geometries, fundamental frequencies, and energies for each of the stationary points of the decomposition pathway are computed using ab initio methods up to CCSDT(Q). Decomposition rates are calculated over a range of temperatures using canonical transition state theory in order to determine the kinetic stability of pentazole. Based on the present results, it would be difficult for pentazole to act as an HEDM, requiring temperatures close to 200 K to achieve a suitable level of stability.

A novel all-nitrogen molecular crystal N16 as a promising high-energy-density material

“…At 1000 K, the energy progressively decreases with no obvious intermediate stages, and all the N 5 units in the crystal are decomposed by the end of the simulation. The decomposition pathway of pentazole has been studied, 61 and the results show that the pentazole ring prefers to lose a nitrogen molecule to form azide. This is the same as what we found in N 10 44 and N 16 molecular crystal decompositions.…”

Pentazolate Anion: A Rare and Preferred Five‐Membered Ligand for Constructing Pentasil‐Zeolite Topology Architectures

“…fluoropentazole and aminopentazole) to date has gained rather good advances, which would establish the foundation for the forthcoming exploration. [55][56][57][58][59] However, as a novel annular full-nitrogen-donor ligand, cyclo-N 5…”

“…But with the deepening investigations, theoretical research for the reaction activity and kinetic stability of cyclo ‐N 5 − and its derivatives (e.g. fluoropentazole and aminopentazole) to date has gained rather good advances, which would establish the foundation for the forthcoming exploration [55–59] . However, as a novel annular full‐nitrogen‐donor ligand, cyclo ‐N 5 − exhibits great possibilities in the realm of coordination chemistry [48] .…”

Enhancing Stability in Polynitrogen Compounds: Mechanisms and Strategies

“…At present, the explosive energy of traditional CHNO explosive is only two times TNT equivalent, which is close to the theoretical limit and difficult to significantly improve. , Compared to traditional energetic materials, polynitrogen compounds have advantages with high density, high enthalpy of formation, ultrahigh energy, and clean and pollution-free detonation products. Therefore, they have the hope to apply as a new generation of ultrahigh energy energetic materials. − A polynitrogen compound represented by a pentazolate anion was successfully synthesized in 2017, and pentazolate salts can stably exist at room temperature. − In contrast to the pentazolate anion, the study of other polynitrogen compounds has remained in theoretical studies and experimental synthesis under extreme conditions such as ultrahigh temperature and ultrahigh pressure. − Only an azide anion and a pentazolate anion were synthesized and stabilized under general reaction conditions, while the synthesis of neutral polynitrogen compounds has not yet been resolved. , The main reason is that feasible synthetic routes for neutral polynitrogen compounds are extremely challenging. The risk of forming transition metal azides and pentazolate salts is too high, particularly.…”