Heptanitrocubane

Octanitrocubane (ONC) has a density of 1.979 g/cm, a calculated heat of formation of 594 kJ/mol, and a decomposition temperature above 200 °C. The explosive performance of octanitrocubane (41) from theoretical calculations is predicted to be exdemely high. The most recent theoretical estimate "" of VOD is 9900 m/s, making this compound one of the most powerful explosives synthesized to date. Surprisingly, the density of heptanitrocubane... 

Nitrocubanes are probably the most powerful explosives with a predicted detonation velocity of >10,000 ms-1. Cubanes were first synthesised at the University of Chicago, USA by Eaton and Cole in 1964. The US Army Armament Research Development Centre (ARDEC) then funded development into the formation of octanitrocubane [(ONC) (C8N8016)] and heptanitrocubane [(HpNC) (C8N7014)]. ONC and HpNC were successfully synthesised in 1997 and 2000 respectively by Eaton and co-workers. The basic structure of ONC is a cubane molecule where all the hydrogens have been replaced by nitro groups (1.6). HpNC is denser than ONC and predicted to be a more powerful, shock-insensitive explosive. 

Heptanitrocubane (125) is easily soluble in polar solvents, such as acetone, THE, and dichloromethane. Single crystal X-ray analysis of 125 has provided an accurate density at 21 °C of 2.028 g cm and showed many intermolecular contacts around each molecule. A solution of 125 in methanol turned yellow which may be due to the anion. Octanitrocubane (128) is a stable, white solid and somewhat soluble in hexane but readily soluble in polar organics. Characterization of 128 was based on single crystal X-ray analysis [115]. 

---