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Preparation of a neutral nitrogen allotrope hexanitrogen C2h-N6

nature.com

1–10 of 30 posts

Re: Preparation of a neutral nitrogen allotrope hexanitrogen C2h-N6

#2
Note that "C2h" is the symmetry[1] and "N6" is the chemical formula. Yes, 6 Nitrogen in a line, N-N-N-N-N-N with some weird bounds and internal charges, probably a good candidate to "Things I Won't Work With" in https://www.science.org/blogs/pipeline From the article:

> Detonation calculation details

[1] See for example another molecule with a different shape but the same symmetry in https://www.cup.uni-muenchen.de/ch/compchem/geom/sym_C2h.htm...

Re: Preparation of a neutral nitrogen allotrope hexanitrogen C2h-N6

#3

Note that "C2h" is the symmetry[1] and "N6" is the chemical formula. Yes, 6 Nitrogen in a line, N-N-N-N-N-N with some weird bounds and internal charges, probably a good candidate to "Things I Won't Work With" in https://www.science.org/blogs/pipeline From the article: > Detonation calculation details [1] See for example another molecule with a different shape but the same symmetry in https://www.cup.uni-muenchen.de/c…

Isn’t it a ring shape?

Re: Preparation of a neutral nitrogen allotrope hexanitrogen C2h-N6

#4
post #3

Note that "C2h" is the symmetry[1] and "N6" is the chemical formula. Yes, 6 Nitrogen in a line, N-N-N-N-N-N with some weird bounds and internal charges, probably a good candidate to "Things I Won't Work With" in https://www.science.org/blogs/pipeline From the article: > Detonation calculation details [1] See for example another molecule with a different shape but the same symmetry in https://www.cup.uni-muenchen.de/c…

Isn’t it a ring shape?

No, it's almost linear with a small glitch in the center https://www.nature.com/articles/s41586-025-09032-9/figures/4

Re: Preparation of a neutral nitrogen allotrope hexanitrogen C2h-N6

#5
> [Nitrogen compounds] are considered promising clean energy-storage materials owing to their immense energy content that is much higher than hydrogen, ammonia or hydrazine, which are in common use, and because they release only harmless nitrogen on decomposition.

What the abstract mentions only sideways is that a key use of these properties is production of explosives - nitroglycerin, trinitrotoluene (TNT) or nitrocellulose (modern gunpowder) come to mind, and indeed, they store a lot of energy. Note all have "nitro" in the name.

At this point I'm not sure you care that only exhaust gas is nitrogen.

Re: Preparation of a neutral nitrogen allotrope hexanitrogen C2h-N6

#6
- "decomposition of N6 into three N2 is exothermic (ΔH₀) by 185.2 kcal mol−1"

That's an impressive amount of energy, 9.2e6 J/kg—on the same order as carbon combustion. Wonder if it's a potential rocket fuel additive (it probably isn't, but fun to ask). By comparison, O₃ is "only" 3.0e6 J/kg above diatomic oxygen.

> "is unlikely to decompose through [quantum mechanical tunneling], with an estimated half-life of N6 of more than 132 years at 77 K (Supplementary Table 4). At 298 K, the computed half-life still amounts to 35.7 ms"

Better hope that fridge doesn't fail.

Re: Preparation of a neutral nitrogen allotrope hexanitrogen C2h-N6

#8

> [Nitrogen compounds] are considered promising clean energy-storage materials owing to their immense energy content that is much higher than hydrogen, ammonia or hydrazine, which are in common use, and because they release only harmless nitrogen on decomposition. What the abstract mentions only sideways is that a key use of these properties is production of explosives - nitroglycerin, trinitrotoluene (TNT) or nitroc…

Hexanitrogen? Nice, but Octanitrocubane is what GURPS promised for TL9.

Found in the warhead table, yes: this is "cleaner" explosives, but military is not spending billions to safe the environment. But get a higher TNT-equivalent per kilogram.

Re: Preparation of a neutral nitrogen allotrope hexanitrogen C2h-N6

#9
The best part is the Methods section, which opens with

> Warning! Silver azide and halogen azides are extremely hazardous and explosive. Such compounds should be handled with utmost care and only in very small quantities (That is, please do the synthesis in full armor, in the dark and don't touch anything more than strictly necessary.

Also wear ear protection, because it's still going to go bang.

I like the green energy twist in the intro too. "High-energy materials" is an euphemism chemists engaged in weapons research like to use. I went to some conference talks about high energy materials before, and research presented at those talks was always funded by various defence agencies. But maybe that's just a North American thing, this particular group only acknowledges funding from the innocuous Deutsche Forschungsgemeinschaft.

Re: Preparation of a neutral nitrogen allotrope hexanitrogen C2h-N6

#10

- "decomposition of N6 into three N2 is exothermic (ΔH₀) by 185.2 kcal mol−1" That's an impressive amount of energy, 9.2e6 J/kg—on the same order as carbon combustion. Wonder if it's a potential rocket fuel additive (it probably isn't, but fun to ask). By comparison, O₃ is "only" 3.0e6 J/kg above diatomic oxygen. > "is unlikely to decompose through [quantum mechanical tunneling], with an estimated half-life of N6 of…

I guess you could have it as some sort of monopropellant? Have some cryogenically cooled N6 flow to the combustion chamber, where it heats up and self-decomposes. Initially you'd have to have some other form of thermal energy input to start the process but once it's going the heat coming off the reaction will trigger further reactions. One downside would be that you'd have much more trouble cooling the engine. Normal engines use the cold fuel and oxidizer flowing around the bell and the combustion chamber to cool them down, but with N6 heating it up before it hits the reaction chamber might be impractical. It would probably be a Bad Thing if it starts self-decomposing while still in the fuel lines...
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