The here described potential belongs to the type of Reax potentials, which is designed to describe interactions between condensed carbon phases (like graphene, diamond etc) and molecules composed of C, H, O and/or N atoms. It is a hybrid potential combining two other Reax potentials, namely the C-2013 potential (Srinivasan, S. G., van Duin, A. C. T., and Ganesh, P., J. Phys. Chem. A 119, 571–580 (2015)) for carbon condensed phases and RDX potential (Strachan, A., van Duin, A. C. T., Chakraborty, D., Dasgupta, S., and Goddard, W. A., Phys. Rev. Lett. 91, 098301 (2003)) for interactions between C/H/O/N atoms and molecules composed of C/H/O/N atoms, originally designed to describe initial chemical events in nitramine RDX explosions. The potential considers a hypothetical new species denoted as Cg, representing the carbon atoms in condensed carbon phases, and C, representing the carbon atoms in all other cases. The interactions between C/H/O/N atoms are described by the RDX potential, while the interactions between Cg-Cg atoms are described by a slightly modified C-2013 potential. Moreover, the interactions between Cg-C, Cg-H, Cg-O and Cg-N are also described by RDX potential, as if Cg was a C atom. The modification of GR-RDX-2021 potential with respect to the C-2013 for the Cg-Cg interactions has to do with the 39 general parameters of the potential, which has been chosen to be the parameters of the RDX potential.