Octaazacubane

Octaazacubane
Names
IUPAC name
Octaazacubane
Other names
Octaazapentacyclo[4.2.0.02,5.03,8.04,7]octane; Cubaazane; Nitrogen octaatomic molecule
Identifiers
3D model (JSmol)
ChemSpider
  • InChI=1S/N8/c1-2-5-3(1)7-4(1)6(2)8(5)7
    Key: QKLIVIBCUWQEME-UHFFFAOYSA-N
  • N12N3N4N1N5N4N3N52
Properties
N8
Molar mass 112.056 g·mol−1
Density 2.69 g/cm3 (predicted)[1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Octaazacubane is a hypothetical explosive allotrope of nitrogen with formula N8, whose molecules have eight atoms arranged into a cube. (By comparison, nitrogen usually occurs as the diatomic molecule N2.) It can be regarded as a cubane-type cluster, where all eight corners are nitrogen atoms bonded along the edges.[2] It is predicted to be a metastable molecule, in which despite the thermodynamic instability caused by bond strain, and the high energy of the N–N single bonds, the molecule remains kinetically stable for reasons of orbital symmetry.[3]

Explosive and fuel

Octaazacubane is predicted to have an energy density (assuming decomposition into N2) of 22.9 MJ/kg,[4] which is over 5 times the standard value of TNT. It has therefore been proposed (along with other exotic nitrogen allotropes) as an explosive, and as a component of high performance rocket fuel. Its velocity of detonation is predicted to be 15,000 m/s, much (48.5%) more than octanitrocubane, the fastest known nonnuclear explosive.[1]

A prediction for cubic gauche nitrogen energy density is 33 MJ/kg, exceeding octaazacubane by 44%,[5] though a more recent one is of 10.22 MJ/kg, making it less than half of octaazacubane.[6]

See also

References

  1. ^ a b Agrawal, Jai Prakash (2010). "2.3 Future Scope for Research". High Energy Materials: Propellants, Explosives and Pyrotechnics. Wiley-VCH. p. 147. ISBN 978-3-527-62880-3.
  2. ^ B. Muir. "Cubane". (in "Further Topics" section).
  3. ^ Patil, Ujwala N.; Dhumal, Nilesh R.; Gejji, Shridhar P. (2004). "Theoretical studies on the molecular electron densities and electrostatic potentials in azacubanes". Theoretical Chemistry Accounts: Theory, Computation, and Modeling. 112: 27–32. doi:10.1007/s00214-004-0551-2. S2CID 97322279.
  4. ^ Glukhovtsev, Mikhail N.; Jiao, Haijun; Schleyer, Paul von Ragué (1996). "Besides N2, What Is the Most Stable Molecule Composed Only of Nitrogen Atoms?". Inorganic Chemistry. 35 (24): 7124–7133. doi:10.1021/ic9606237. PMID 11666896.
  5. ^ Yoo, Choong-Shik (February 2003). "Novel Functional Extended Solids at Extreme Conditions" (PDF). DTIC. p. 11. Archived from the original on March 4, 2016. Retrieved 5 October 2015.
  6. ^ Bondarchuk, Sergey V.; Minaev, Boris F. (2017). "Super high-energy density single-bonded trigonal nitrogen allotrope—a chemical twin of the cubic gauche form of nitrogen". Physical Chemistry Chemical Physics. 19 (9). The Royal Society of Chemistry: 6698–6706. Bibcode:2017PCCP...19.6698B. doi:10.1039/C6CP08723J. PMID 28210733.