An X-ray crystallographic study of 2,2 '',4,4',4 '',6,6',6 ''-octanitro-1,1' :3',1 ''-terphenyl (ONT) has been carried out. The dihedral angle between benzene rings vary from 84.9 degrees to 89.4 degrees. Non-binding interatomic distances of oxygen atoms inside all the nitro groups are shorter than the intermolecular contact radii for oxygen. On the basis of the DFT B3LYP/6-31(d, p) method it was found that the difference between the X-ray structure in the solid phase and DFT result for the gas phase is 98 kJ mol(-1), and the bearer of the highest initiation reactivity of the ONT molecule in the solid phase should be the nitro group at 4 ''-position, in contrast to those at 4'- or 6'-position that play this role in the isolated molecule. It has been stated that the nitro groups at the reaction centers of the ONT molecule are relatively well specified by their (15)N NMR chemical shifts.