Theoretical investigation on the interaction mechanism of FOX-7/AP mixed crystals

ABSTRACT

Herein, in order to determine the formation feasibility of 1,1-diamino-2,2-dinitroethylene (FOX-7)/ ammonium perchlorate (AP) mixed crystals, three configurations of FOX-7/AP composites (FOX-7/AP1, FOX-7/AP2, FOX-7/AP3) were optimised, and the structures of FOX-7/AP mixed crystals were constructed. Then the electrostatic potential, binding energy and electronic density topology of FOX-7/AP composites were calculated by using the density functional theory. Finally, the radial distribution function between H atoms and O atoms of FOX-7/AP mixtures was calculated through molecular dynamics. As demonstrated by the results, there are hydrogen bond interactions in three configurations of FOX-7/AP composites. The interaction energies of FOX-7/AP1, FOX-7/AP2 and FOX-7/AP3 are 8.396, 20.537 and 38.189 kJ▪mol⁻¹, respectively. The order of the electron density ρ(r) at the bond critical point (BCP) of three FOX-7/AP composites is FOX7-AP3 > FOX7-AP2 > FOX7-AP1. There are apparent peaks at the range of 0.11–0.31 nm and 0.31–0.5 nm for FOX-7(10-1)/AP, FOX-7(011)/AP, FOX-7(101)/AP mixed crystals. The interaction strength of the hydrogen bond is greater than that of strong van der Waals force. Therefore, it is feasible to combine FOX-7 with AP to form mixed crystals. As the content of AP in the mixed crystal is on the rise, the oxygen balance of the system shows a gradually increasing trend.

KEYWORDS:

• 1,1-Diamino-2,2-dinitroethylene (FOX-7)
• ammonium perchlorate (AP)
• density functional theory
• molecular dynamics
• mixed crystals

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by National Natural Science Foundation of China [grant number 11502194].