Structural Study of RDX, HMX and their Derivatives with Density Functional Theory and Calculation of Some of their Properties

The hexogen, RDX and cyclotetramethylene-tetranitramine (HMX) are of the strongest explosives known to be classified as secondary explosives. These compounds, and some other similar compounds, have N-N and N-O covalent bonds, which appear to be an important factor in their explosive and energetic properties. In this paper, the optimal structures and energies of the RDX and HMX and also the energy and structure of some other similar compounds are studied and compared. The selected compounds have an equal number of atoms and in the structure of all of them, the skeletons of 1,3,5-triazine and 1,3,5,7-tetraazine are preserved and the effect of other functional groups such as NH2 and N3 has been investigated. The results of calculations based on density functional theory showed that the amount of energy and structure stability of these compounds depends on the kind of functional groups and the way they are connected to the main ring. Dense phase heat of formation, crystalline density, detonation velocity and detonation pressure for the selected compounds were calculated.