A first‐principles investigation of the hydrogen bond interaction and the sensitive characters in cis‐1,3,4,6‐tetranitrooctahydroimidazo‐[4,5‐d]imidazole

Abstract

A theoretical study of structural and electronic properties of cis-1,3,4,6-tetranitrooctahydroimidazo- [4,5-d]imidazole (BCHMX) crystal is performed using density functional theory. The band structure, the total density of states, the atomic orbit projected density of states (PDOS) of C, N, O, and H, and Mulliken population analysis are discussed. The study by analyzing the PDOS shows that the structure of BCHMX crystal possesses CAHÁÁÁO intra-and intermolecular hydrogen bonding. There are hydrogen bonds between H 3 -1s and O 5 -2p orbits, H 2 -1s and O 6 -2p orbits of intramolecules and between H 2 -1s and O 1 -2p orbits of intermolecules. The reasons for the smaller impact sensitivity compared with b-1,3,5,7-tetranitro-1,3,5,7-tetrazocane and 1,3,5-trinitro-1,3,5-triazinane are also explored from the band gap in the crystal and the weakest bond dissociation energy in single molecule.

Theoretical evaluation of sensitivity and thermal stability for high explosives based on quantum chemistry methods: A brief review

“…[42] However, it is still necessary and useful to carry out correlation studies to identify molecular properties that indicate impact sensitivity. [43] In fact, Chen and Cheng [44] discovered a relationship between the electronic properties (band gap) of cis-1,3,4,6-tetranitrooctahydroimidazo- [4,5-d]imidazole (BCHMX) and its impact sensitivity. Besides, according to Zeman, [45] Huang, [46] and Wang, [47,48] impact sensitivity is also dependent on the electrotopological state indices.…”

The mechanisms for desensitization effect of synthetic polymers on BCHMX: Physical models and decomposition pathways

“…As shown in Fig. 2, there are obviously two steps involved in decomposition of pure BCHMX, and it has to be separated for reliable kinetic evaluation, which has been done in the authors' previous paper [11]. For BCHMX-VA, BCHMX-SE and BCHMX-C4, there are also very small steps (less than 5% contribution to the whole mass loss) before the main decomposition process, which are very dependent on the heating rate.…”

“…There might be some interaction between the polymer chains and BCHMX molecules during LH, making BCHMX decompose slower at the beginning. A visual melting point of BCHMX was found at 268 • C under LH conditions [4], but no endothermic peak was detected before its onset decomposition by means of DTA and DSC [6,11]. However, exposure of BCHMX at 190 • C only for 30 min leads to partial melting (dissolving in products of its decomposition) and thermolysis on its crystal surface with defects and voids, which is caused by so-called topochemical reaction that usually occurs at the boundary of solid phases [11].…”

“…Firstly, the master plots method has been used for determination of the kinetic models on the basis of characterized shape function z(˛) and y(˛) [34][35][36]. The authors have summarized and interpreted this method elsewhere before [11,30] and in this paper only the Johnson-Mehl-Avrami (JMA, Eq. (1)) and autocatalytic (AC, Eq.…”

“…The binders based on these polymers including Formex P1, Semtex 10 and C4 have strong effect on the reactivity of BCHMX by slowing down its decomposition reaction with higher energy barriers [11]. Such polymer matrices could, therefore, significantly decrease the impact sensitivity of BCHMX, while Fluoropolymers have only a little positive effect on that [16].…”