ImportMaster at 16:06, 21 April 2022

2022-04-21T16:06:34Z

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{{Chembox
| Verifiedfields = changed
| Watchedfields = changed
| verifiedrevid = 451734664
| ImageFileL1 = CL-20.svg
| ImageFileL1_Ref = {{chemboximage|correct|??}}
| ImageSizeL1 = 121
| ImageNameL1 = Partially condensed, stereo, skeletal formula of hexanitrohexaazaisowurtzitane
| ImageFileR1 = HNIW-3D-balls.png
| ImageFileR1_Ref = {{chemboximage|correct|??}}
| ImageSizeR1 = 121
| ImageNameR1 = Ball and stick model of hexazaisowurtzitane
| IUPACName = 2,4,6,8,10,12-Hexanitro-2,4,6,8,10,12-hexaazatetracyclo[5.5.0.03,11.05,9]dodecane
| OtherNames = {{Unbulleted list
| CL-20
| Hexanitrohexaazaisowurtzitane
| 2,4,6,8,10,12-Hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane
| Octahydro-1,3,4,7,8,10-hexanitro-5,2,6-(iminomethenimino)-1H-imidazo[4,5-b]pyrazine
| HNIW
}}
|Section1={{Chembox Identifiers
| Abbreviations = CL-20, HNIW
| CASNo_Ref = {{cascite|correct|??}}
| CASNo = 135285-90-4
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = RQM82X0CL7
| PubChem = 9889323
| PubChem1 = 11048432
| PubChem1_Comment = (3''R'',9''R'')-dodec
| PubChem2 = 11419235
| PubChem2_Comment = (3''R'',5''S'',9''R'',11''S'')- dodec
| ChemSpiderID = 8064994
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID1 = 9223599
| ChemSpiderID1_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID1_Comment = (3''R'',9''R'')-dodec
| ChemSpiderID2 = 9594121
| ChemSpiderID2_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID2_Comment = (3''R'',5''S'',9''R'',11''S'')- dodec
| ChEBI_Ref = {{ebicite|changed|EBI}}
| ChEBI = 77327
| SMILES = [O-][N+](=O)N1C2C3N(C4C(N3[N+]([O-])=O)N(C(C1N4[N+]([O-])=O)N2[N+]([O-])=O)[N+]([O-])=O)[N+]([O-])=O
| StdInChI = 1S/C6H6N12O12/c19-13(20)7-1-2-8(14(21)22)5(7)6-9(15(23)24)3(11(1)17(27)28)4(10(6)16(25)26)12(2)18(29)30/h1-6H
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = NDYLCHGXSQOGMS-UHFFFAOYSA-N
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
}}
|Section2={{Chembox Properties
| Formula = {{Chem|C|6|N|12|H|6|O|12}}
| MolarMass = 438.1850 g mol−1
| Density = 2.044 g cm−3
}}
|Section6={{Chembox Explosive
| DetonationV = 9,500 [[metre per second|m/s]]
| REFactor = 1.9 }}
}}

'''Hexanitrohexaazaisowurtzitane''', also called '''HNIW''' and '''CL-20''', is a [[nitroamine]] explosive with the formula C6H6N12O12. The structure of CL-20 was first proposed in 1979 by [[Dalian Institute of Chemical Physics]].<ref>{{cite web |url=http://www.bit.edu.cn/xww/lgxb21/123759.htm |title=北理工的爆轰速度中国力量的可靠基石 |author=王征, 和霄雯 |publisher=北京理工大学新闻网 |date=2016-04-19 |access-date=2016-05-03 |archive-date=2016-05-07 |archive-url=https://web.archive.org/web/20160507123647/http://www.bit.edu.cn/xww/lgxb21/123759.htm |url-status=live }}</ref> In the 1980s, CL-20 was developed by the [[Naval Air Weapons Station China Lake|China Lake]] facility, primarily to be used in [[propellant]]s. It has a better [[Redox|oxidizer]]-to-[[fuel]] ratio than conventional [[HMX]] or [[RDX]]. It releases 20% more energy than traditional HMX-based propellants, and is widely superior to conventional high-energy propellants and explosives.{{Citation needed|date=May 2020}}

Industrial production of CL-20 was achieved in [[China]] in 2011, and it was soon fielded in propellant of [[solid rocket]]s.<ref>{{cite web |url=http://www.bit.edu.cn/xww/lgxb21/123905.htm |title=我们要在宇宙空间占一个位置！ |author=黎轩平 |publisher=北京理工大学新闻网 |date=2016-04-23 |access-date=2016-05-03 |archive-date=2016-05-07 |archive-url=https://web.archive.org/web/20160507123650/http://www.bit.edu.cn/xww/lgxb21/123905.htm |url-status=live }}</ref> While most development of CL-20 has been fielded by the [[Thiokol|Thiokol Corporation]], the [[US Navy]] (through [[Office of Naval Research|ONR]]) has also been interested in CL-20 for use in [[rocket propellant]]s, such as for [[missiles]], as it has lower observability characteristics such as less visible smoke.<ref>{{cite web |url=http://www.physorg.com/news/2011-09-university-chemists-stabilize-explosive-cl-.html |title=University chemists devise means to stabilize explosive CL-20 |first=Bob |last=Yirka |publisher=Physorg.com |date=9 September 2011 |accessdate=8 July 2012 |archive-date=25 January 2021 |archive-url=https://web.archive.org/web/20210125151129/https://phys.org/news/2011-09-university-chemists-stabilize-explosive-cl-.html |url-status=live }}</ref>

CL-20 has not yet been fielded in any production weapons system, but is undergoing testing for stability, production capabilities, and other weapons characteristics.

== Synthesis ==
[[File:Synthesis CL20.svg|thumb|left|Synthesis of CL20]]

First, [[benzylamine]] ('''1''') is condensed with [[glyoxal]] ('''2''') under acidic and dehydrating conditions to yield the first intermediate compound.('''3'''). Four benzyl groups selectively undergo [[hydrogenolysis]] using [[palladium on carbon]] and hydrogen. The amino groups are then acetylated during the same step using [[acetic anhydride]] as the solvent. ('''4'''). Finally, compound '''4''' is reacted with [[nitronium tetrafluoroborate]] and [[nitrosonium tetrafluoroborate]], resulting in HNIW.<ref>{{cite journal|journal = [[Combust. Explos. Shock Waves]]|year = 2005|volume = 41|issue = 2|pages = 121–132|title = Hexanitrohexaazaisowurtzitane (CL-20) and CL-20-based formulations (review)|first1 = U. R.|last1 = Nair|first2 = R.|last2 = Sivabalan|first3 = G. M.|last3 = Gore|first4 = M.|last4 = Geetha|first5 = S. N.|last5 = Asthana|first6 = H.|last6 = Singh|doi = 10.1007/s10573-005-0014-2|s2cid = 95545484}}</ref>

==Cocrystal product with HMX==
In August 2012, [[Onas Bolton]] et al. published results showing that a [[cocrystal]] of 2 parts CL-20 and 1 part [[HMX]] had similar safety properties to HMX, but with a greater firing power closer to CL-20.<ref>{{cite journal|doi=10.1021/cg3010882 | volume=12 | issue=9 | title=High Power Explosive with Good Sensitivity: A 2:1 Cocrystal of CL-20:HMX | year=2012 | journal= Crystal Growth & Design| pages=4311–4314 | last1 = Bolton | first1 = Onas}}</ref><ref>[http://www.spacewar.com/reports/Powerful_new_explosive_could_replace_todays_state_of_the_art_military_explosive_999.html Powerful new explosive could replace today's state-of-the-art military explosive] {{Webarchive|url=https://web.archive.org/web/20120909160217/http://www.spacewar.com/reports/Powerful_new_explosive_could_replace_todays_state_of_the_art_military_explosive_999.html |date=2012-09-09 }}, SpaceWar.com, 6 September 2012, accessed 7 September 2012</ref>

==Cocrystal product with TNT==
In August 2011, [[Adam Matzger]] and [[Onas Bolton]] published results showing that a [[cocrystal]] of CL-20 and [[TNT]] had twice the stability of CL-20—safe enough to transport, but when heated to {{convert|136|°C|°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.<ref>{{cite journal|doi=10.1002/anie.201104164 | pmid=21901797 | volume=50 | issue=38 | title=Improved Stability and Smart-Material Functionality Realized in an Energetic Cocrystal | year=2011 | journal=Angewandte Chemie International Edition | pages=8960–8963 | last1 = Bolton | first1 = Onas| hdl=2027.42/86799 | hdl-access=free }}</ref><ref>{{Cite web |url=http://blogs.sciencemag.org/pipeline/archives/2011/11/11/things_i_wont_work_with_hexanitrohexaazaisowurtzitane |title=Things I Won't Work With: Hexanitrohexaazaisowurtzitane |date=11 November 2011 |access-date=2016-01-04 |archive-date=2015-09-03 |archive-url=https://web.archive.org/web/20150903002615/http://blogs.sciencemag.org/pipeline/archives/2011/11/11/things_i_wont_work_with_hexanitrohexaazaisowurtzitane |url-status=live }}</ref>

==CL-20 covalent chains and networks==
In 2017, K.P. Katin and M.M. Maslov designed one-dimensional covalent chains based on the CL-20 molecules.<ref name=katin2017>{{cite journal|doi=10.1016/j.jpcs.2017.04.020 | volume=108 | title=Toward CL-20 crystalline covalent solids: On the dependence of energy and electronic properties on the effective size of CL-20 chains | year=2017 | journal=[[Journal of Physics and Chemistry of Solids]] | pages=82–87 | last1 = Katin | first1 = Konstantin P. | last2 = Maslov | first2 = Mikhail M.| arxiv=1611.08623 | bibcode=2017JPCS..108...82K | s2cid=100118824 }}</ref> Such chains were constructed using CH2 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 of CH2 molecular bridges.<ref name=gimaldinova2018>{{cite journal | doi=10.1039/c8ce00763b | volume=20 | issue=30 | title=Electronic and reactivity characteristics of CL-20 covalent chains and networks: a density functional theory study | year=2018 | journal=[[CrystEngComm]] | pages=4336–4344 | last1 = Gimaldinova | first1 = Margarita A. | last2 = Maslov | first2 = Mikhail M. | last3 = Katin | first3 = Konstantin P. }}</ref> It is shown that the use of CH2 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.<ref name="katin2017" /><ref name="gimaldinova2018" />

==See also==
* [[2,4,6-Tris(trinitromethyl)-1,3,5-triazine]]
* [[4,4’-Dinitro-3,3’-diazenofuroxan]] (DDF)
* [[Heptanitrocubane]] (HNC)
* [[HHTDD]]
* [[Iceane]] (Wurtzitane)
* [[Octanitrocubane]] (ONC)
* [[RE factor]]
* [[TEX (explosive)]]

== References ==

{{reflist}}

== Further reading ==

* {{cite journal |title=Improved Stability and Smart-Material Functionality Realized in an Energetic Cocrystal |last=Bolton |first=Onas |author2=Adam J. Matzger |journal=[[Angewandte Chemie]] |volume=123 |issue=38 |pages=9122–9125 |date=September 12, 2011 |doi=10.1002/ange.201104164|pmid=21901797 |bibcode=2011AngCh.123.9122B |hdl=2027.42/86799 |hdl-access=free }}
* Lowe, Derek (11 November 2011) [http://blogs.sciencemag.org/pipeline/archives/2011/11/11/things_i_wont_work_with_hexanitrohexaazaisowurtzitane "Things I won't work with: Hexanitrohexaazaisowurtzitane"]

[[Category:Explosive chemicals]]
[[Category:Nitroamines]]
[[Category:Rocket fuels]]

Hexanitrohexaazaisowurtzitane - Revision history

ImportMaster at 16:06, 21 April 2022