Charge density studies of energetic material: RDX

David Stephen A,Asthana S.N,Rajesh B Pawar Rajesh B Pawar,Kumuradhas P

doi:10.34256/famr2011

Abstract

Experimental charge density study has been carried out for Cyclotrimethylene-trinitramine (space group Pbca), an explosive material from a low temperature X-ray diffraction experiment. The electron density was modeled using the Hansen-Coppens multipole model and refined to R=0.032 for 6226 unique observed reflections. The electron density, laplacian and electrostatic potential distributions are reported and discussed, especially, the properties of the bond (3,-1) critical points, which are thought to play a key role in the decomposition of the molecule. From the bond topological analysis of all the bonds, it is observed that the N–N bond is the weakest. The dominating nature of the oxygen atoms was clearly well understood from isosurface electrostatic potential of isolated and symmetrically sitting molecules in the crystal.

Highlights

Explosives, the energetic material, that was unstable either chemically or energetically and upon initiation, it produces a sudden expansion accompanied by the production of heat and large changes in pressure [1]
The series of charge density studies on propellants and explosives eg. 5-nitro-2,4-dihyro-3H-1,2,4-triazol-3-one (NTO) [6], two biguanidinium dinitramides [7], pentaerythritol tetranitrate [8], 1,3,4-trinitro-7,8-diazapentalene [9], 3,5,9,11-tetraacetyl-14-oxo1,3,5,7,9,11-hexaazapenta-cyclo-[5.5.3.02,6.04,10.08,12] pentadecane (CL-20) [10], 1,1diamino-2,2-dinitro ethylene (FOX-7) [10], were carried out and in these studies, the insights of electron density distribution of these molecules were summarized using high resolution experimental diffraction data. As sustain of this series, in this work, we investigate the energetic material RDX (Cyclotrimethylene-trinitramine) from X-ray diffraction experiment
We do the experimental electron density investigation based on high resolution X-ray diffraction data obtained at low temperature

Summary

Introduction

Explosives, the energetic material, that was unstable either chemically or energetically and upon initiation, it produces a sudden expansion accompanied by the production of heat and large changes in pressure [1]. As the conventional single crystal structure determination fails to interpret the chemical bonding nature of the molecules at electronic level, an extensive high resolution diffraction data was required to explicit the charge density distribution in the bonding The average electron density in C–H bond regions of the six membered ring was ~1.83 eÅ-3, with the polarity values close to 17.5% towards hydrogen.

Results

Conclusion