The structure, activation energy, onset temperature, heat of formation, and calculated detonation properties of 1,4-bis(trinitromethly)benzene are reported here. The crystal structure of this compound shows that as other trinitromethyl containing compounds the planes of the three independent C-NO2 are approximately perpendicular to one another. The crystal density is 1.805 g/cm(3). Like other trinitromethyl containing explosives, the onset temperature is relatively low (103.7 degrees C). The incorporation of two trinitromethly groups yields a reasonable oxygen balance (-25.5 %) which is close to that of RDX (-21.6 %). While the calculated detonation velocity of HNX exceeds that of TNT it is almost 6 % lower than that of RDX.