Octanitrocubane (molecular formula: C₈(NO₂)₈) is a

high explosive An explosive (or explosive material) is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure. An exp ...

that, like

TNT Trinitrotoluene (), more commonly known as TNT, more specifically 2,4,6-trinitrotoluene, and by its preferred IUPAC name 2-methyl-1,3,5-trinitrobenzene, is a chemical compound with the formula C6H2(NO2)3CH3. TNT is occasionally used as a reagen ...

, is shock-insensitive (not readily

detonate Detonation () is a type of combustion involving a supersonic exothermic front accelerating through a medium that eventually drives a shock front propagating directly in front of it. Detonations propagate supersonically through shock waves with s ...

d by shock). The octanitrocubane molecule has the same

chemical structure A chemical structure determination includes a chemist's specifying the molecular geometry and, when feasible and necessary, the electronic structure of the target molecule or other solid. Molecular geometry refers to the spatial arrangement of at ...

cubane Cubane () is a synthetic hydrocarbon compound that consists of eight carbon atoms arranged at the corners of a cube, with one hydrogen atom attached to each carbon atom. A solid crystalline substance, cubane is one of the Platonic hydrocarbons an ...

(C₈H₈) except that each of the eight

hydrogen Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic, an ...

atoms is replaced by a

nitro group In organic chemistry, nitro compounds are organic compounds that contain one or more nitro functional groups (). The nitro group is one of the most common explosophores (functional group that makes a compound explosive) used globally. The nitr ...

(NO₂). It is however not as powerful an explosive as once thought, as the high-density theoretical crystal structure has not been achieved. For this reason

heptanitrocubane Heptanitrocubane is an experimental high explosive based on the cubic eight-carbon cubane molecule and closely related to octanitrocubane. Seven of the eight hydrogen atoms at the corners of the cubane molecule are replaced by nitro groups, g ...

, 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 physics, potential energy is the energy held by an object because of its position relative to other objects, stresses within itself, its electric charge, or other factors. Common types of potential energy include the gravitational potentia ...

. In addition, it produces no water vapor upon combustion, making it less visible, and both the chemical itself and its decomposition products (

nitrogen Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...

and

carbon dioxide Carbon dioxide (chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is transpar ...

) are considered to be non-toxic. Octanitrocubane was first synthesized by

Philip Eaton Philip E. Eaton (born 1936) is a Professor Emeritus of Chemistry at the University of Chicago. He and his fellow researchers were the first to synthesize the "impossible" cubane molecule in 1964.P. Eaton and T. W. Cole, The Cubane System, J. Am. C ...

(who was also the first to synthesize cubane in 1964) and Mao-Xi Zhang at the

University of Chicago The University of Chicago (UChicago, Chicago, U of C, or UChi) is a private research university in Chicago, Illinois. Its main campus is located in Chicago's Hyde Park neighborhood. The University of Chicago is consistently ranked among the b ...

in 1999, with the structure proven by crystallographer Richard Gilardi of the

United States Naval Research Laboratory The United States Naval Research Laboratory (NRL) is the corporate research laboratory for the United States Navy and the United States Marine Corps. It was founded in 1923 and conducts basic scientific research, applied research, technological ...

. Not enough has been synthesized, though, for performance testing as an explosive. Octanitrocubane has a

detonation velocity Explosive velocity, also known as detonation velocity or velocity of detonation (VoD), is the velocity at which the shock wave front travels through a detonated explosive. Explosive velocities are always faster than the local speed of sound in the ...

of 10,100 m/s, making it the fastest known explosive. Its

R.E. factor TNT equivalent is a convention for expressing energy, typically used to describe the energy released in an explosion. The is a unit of energy defined by that convention to be , which is the approximate energy released in the detonation of a t ...

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

(rare enough to begin with) as a starting point. As a result, octanitrocubane is more valuable, gram for gram, than

gold Gold is a chemical element with the symbol Au (from la, aurum) and atomic number 79. This makes it one of the higher atomic number elements that occur naturally. It is a bright, slightly orange-yellow, dense, soft, malleable, and ductile met ...

A proposed path to synthesis is the cyclotetramerization of the as yet undiscovered and presumably highly unstable dinitroacetylene.

References

External links

American Chemical Society lauds difficult synthesis of new compound (by Philip Eaton), March 20, 2001

Notes

{{reflist, group=note Explosive chemicals Nitro compounds Substances discovered in the 1990s

Synthesis

See also

References

External links

Notes