Octanitrocubane

Octanitrocubane (molecular formula: C8(NO2)8) is a high explosive that, like TNT, is shock-insensitive (not readily detonated by shock).[1] The octanitrocubane molecule has the same chemical structure as cubane (C8H8) except that each of the eight hydrogen atoms is replaced by a nitro group (NO2).

Octanitrocubane
Names
IUPAC name
Octanitrocubane
Identifiers
3D model (JSmol)
ChemSpider
Properties
C8N8O16
Molar mass 464.128 g·mol−1
Density 1.979 g/cm3
Hazards
Main hazards Explosive compound
Explosive data
Shock sensitivity Low
Friction sensitivity Low
Detonation velocity 10,100 m/s
RE factor 2.38
Related compounds
Related compounds
 Cubane
Heptanitrocubane
Octaazacubane
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

It is however not as powerful as once thought, as the high-density theoretical crystal structure has not been achieved. For this reason heptanitrocubane, the slightly less nitrated form is believed to have marginally better performance despite having a worse oxygen balance.

Octanitrocubane is thought to have 20–25% greater performance than HMX (octogen). This increase in power is due to its highly expansive breakdown into CO2 and N2, as well as to the presence of strained chemical bonds in the molecule which have stored potential energy. In addition, octanitrocubane produces no water vapor making it less visible, and both the chemical itself and its decomposition products (nitrogen and carbon dioxide) are considered to be non-toxic.

Octanitrocubane has a detonation velocity of 10,100 m/s, making it the fastest known explosive.

Small amounts have been synthesized in the laboratory, but not enough for performance testing as an explosive.[2]

Octanitrocubane was first synthesized by Philip Eaton (who was also the first to synthesize cubane in 1964) and Mao-Xi Zhang at the University of Chicago in 1999, with the structure proven by crystallographer Richard Gilardi of the United States Naval Research Laboratory.[3][4]

The R.E. factor of octanitrocubane is 2.38, making it the most effective chemical explosive known.

Synthesis

Although octanitrocubane is predicted to be one of the most effective explosives, the difficulty of its synthesis inhibits practical use. Philip Eaton's synthesis was difficult and lengthy, and required cubane (rare enough to begin with) as a starting point. As a result, octanitrocubane is more valuable, gram for gram, than gold.[5] A proposed path to synthesis is the cyclotetramerization of the as yet undiscovered and presumably highly unstable dinitroacetylene.[note 1][6]

See also

References
  1. "Octanitrocubane: Easier said than done". University of Chicago News Office. March 20, 2001.
  2. Astakhov, A. M.; Stepanov, R. S.; Babushkin, A. Yu. (1998). "On the detonation parameters of octanitrocubane". Combustion Explosion and Shock Waves. 34 (1): 85–87. doi:10.1007/BF02671823.
  3. Zhang, Mao-Xi; Eaton, Philip E.; Gilardi, Richard (2000). "Hepta- and Octanitrocubanes". Angewandte Chemie International Edition. 39 (2): 401–404. doi:10.1002/(SICI)1521-3773(20000117)39:2<401::AID-ANIE401>3.0.CO;2-P. PMID 10649425.
  4. Eaton, Philip E.; Zhang, Mao-Xi; Gilardi, Richard; Gelber, Nat; Iyer, Sury; Surapaneni, Rao (2001). "Octanitrocubane: A New Nitrocarbon". Propellants, Explosives, Pyrotechnics. 27 (1): 1–6. doi:10.1002/1521-4087(200203)27:1<1::AID-PREP1>3.0.CO;2-6.
  5. Krause, Horst H. (2004). "New Energetic Materials" (PDF). In Teipel, Ulrich (ed.). Energetic Materials: Particle Processing and Characterization. pp. 1–25. ISBN 978-3-527-30240-6.
  6. Politzer, Peter; Lane, Pat; Wiener, John J. (8 June 1999). Cyclooligomerizations as Possible Routes to Cubane-Like Systems. ASIN B00IT6MGOK. OCLC 227895131. ADA364287 – via Defense Technical Information Center.

Notes
  1. SMILES string: [N+](=O)([O-])C#C[N+](=O)[O-]
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