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| Names | |||
|---|---|---|---|
| IUPAC name 2,4,6,8,10,12-Hexanitro-2,4,6,8,10,12-hexaazatetracyclo[5.5.0.03,11.05,9]dodecane | |||
Other names
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| Identifiers | |||
3D model (JSmol) | |||
| Abbreviations | CL-20, HNIW | ||
| ChEBI | |||
| ChemSpider | |||
| ECHA InfoCard | 100.114.169 | ||
| UNII | |||
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| Properties | |||
| C 6N 12H 6O 12 | |||
| Molar mass | 438.1850 g mol−1 | ||
| Density | 2.044 g cm−3 | ||
| Explosive data | |||
| Detonation velocity | 9,500m/s | ||
| RE factor | 1.9 | ||
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |||
Hexanitrohexaazaisowurtzitane, also calledHNIW andCL-20, is apolycyclicnitroamine explosive with the formulaC6H6N12O12. It has a betteroxidizer-to-fuel ratio than conventionalHMX orRDX. It releases 20% more energy than traditional HMX-based propellants.
In the 1980s, CL-20 was developed by theChina Lake facility, primarily to be used inpropellants.[1]
While most development of CL-20 has been fielded by theThiokol Corporation, theUS Navy (throughONR) has also been interested in CL-20 for use inrocket propellants, such as formissiles, as it has lower observability characteristics such as less visible smoke.[2]
Thus far, CL-20 has only been used in theAeroVironment Switchblade 300 “kamikaze” drone, but is undergoing testing for use in the Lockheed Martin [LMT]AGM-158C Long Range Anti-Ship Missile (LRASM) and AGM-158B Joint Air-to-Surface Standoff Missile-Extended Range (JASSM-ER).[3]
TheIndian Armed Forces have also looked into CL-20.[4]
The TaiwaneseNational Chung-Shan Institute of Science and Technology innaugerated a CL-20 production facility in 2022 with reported integration into theHF-2 andHF-3 product lines.[5]
First,benzylamine (1) is condensed withglyoxal (2) under acidic and dehydrating conditions to yield the first intermediate compound.(3). Four benzyl groups selectively undergohydrogenolysis usingpalladium on carbon and hydrogen. The amino groups are then acetylated during the same step usingacetic anhydride as the solvent. (4). Finally, compound4 is reacted withnitronium tetrafluoroborate andnitrosonium tetrafluoroborate, resulting in HNIW.[6]
In August 2011,Adam Matzger andOnas Bolton published results showing that acocrystal of CL-20 andTNT had twice the stability of CL-20—safe enough to transport, but when heated to 136 °C (277 °F) the cocrystal may separate into liquid TNT and a crystal form of CL-20 with structural defects that is somewhat less stable than CL-20.[7][8]
In August 2012,Onas Bolton et al. published results showing that acocrystal of 2 parts CL-20 and 1 partHMX had similar safety properties to HMX, but with a greater firing power closer to CL-20.[9][10]
In 2017, K.P. Katin and M.M. Maslov designed one-dimensional covalent chains based on the CL-20 molecules.[11] Such chains were constructed usingCH
2 molecular bridges for the covalent bonding between the isolated CL-20 fragments. It was theoretically predicted that their stability increased with efficient length growth. A year later, M.A. Gimaldinova and colleagues demonstrated the versatility ofCH
2 molecular bridges.[12] It is shown that the use ofCH
2 bridges is the universal technique to connect both CL-20 fragments in the chain and the chains together to make a network (linear or zigzag). It is confirmed that the increase of the effective sizes and dimensionality of the CL-20 covalent systems leads to their thermodynamic stability growth. Therefore, the formation of CL-20 crystalline covalent solids seems to be energetically favorable, and CL-20 molecules are capable of forming not only molecular crystals but bulk covalent structures as well. Numerical calculations of CL-20 chains and networks' electronic characteristics revealed that they were wide-bandgap semiconductors.[11][12]
