6 ms·

Nah. These are all predominantly branched and/or cyclic carbon chains, with a few heteroatoms scattered in for effect. They probably burn well, they might smell

Nah. These are all predominantly branched and/or cyclic carbon chains, with a few heteroatoms scattered in for effect. They probably burn well, they might smell nasty, but they are not going to be explosive. Explosives (or "energetic materials" as they are known in the trade) are generally all about stuffing as many nitrogen and oxygen atoms as possible into your molecule; take TriNitroToluene as an example, it has 7 carbons, 3 nitrogens and 6 oxygens, and that's fairly mild. What these structures remind me most of is what you would find in a sour heavy crude oil. In fact, I can guarantee the person who named this website has never looked at high resolution mass spectroscopy analysis (like an FTICR-MS) of any type of petroleum, or they would have named it "this chemical is probably being pumped out of the ground right now".

dexwiz 5y ago
Yes, practically this means shoving as many nitro groups together. But what makes nitro groups explosive to begin with? From what I remember, the large electron shells of the oxygen atoms repel each other, increasing the bond N-O-N angle by a few degrees. It's very easy to break these stressed bonds, and oxidize another carbon compound with the liberated oxygen, creating CO2 gas (the explosive bit). Some of the most powerful explosives are made by attaching nitro groups to stressed ring or cage structures.
- lmilcin 5y ago
  Whenever I hear of "nitrogen stuffing" I remember https://blogs.sciencemag.org/pipeline/archives/2013/01/09/things_i_wont_work_with_azidoazide_azides_more_or_less https://blogs.sciencemag.org/pipeline/archives/2013/01/09/th...
  - dexwiz 5y ago
    Haha! Perfect example of the "mouse trap".
    - lmilcin 5y ago
      Nothing that has 14 nitrogen atoms to only 2 other atoms in it can be considered a trap. It is bound to be exciting:) (see? "bound", haha, just barely)
- semi-extrinsic 5y ago
  Yeah, you are right that it's very easy to break apart nitro groups, but it's not much to do with the (O-N-O) bond angle. The bonds themselves in -NO2 groups are very weak, because nitrogen doesn't provide enough bonds to make things stable. Remember oxygen wants to "hold on with two hands" as we said in high school chemistry, that is to make a double bond or two single bonds. In NO2 each oxygen only gets one and a half bond (quantum mechanically it is in a superposition between having single bond to the first oxygen and double bond to the second, and vice versa). So this part becomes electronegative. Nitrogen, on the other hand, wants to have three bonds in total, but is forced to have four: 2x 1.5 to the oxygens, and one to the rest of the molecule. So this part becomes electropositive. Chemists will speak here of a resonance structure, which you can imagine is something that it is quite easy to excite. When the nitro group breaks apart, the nitrogen finds another nitrogen from another NO2 and forms N2 gas, which is highly stable due to its triple bond, so this part of the reaction releases a lot of energy and produces a lot of gas, and is very fast since it does not depend on any other sub-reactions. And stuffing lots of just nitrogen (without oxygen) into a molecule is in itself a way to make it very explosive - see azidotetrazolate salts. In NO2 decomposition, the oxygen then goes on to find carbon to make CO2, and hydrogen to make H2O, releasing more energy and producing more gas. But this first requires breaking down the relatively stable bonds in the hydrocarbon, so it actually consumes energy from the NO2 decompostion, before it releases more energy than it consumed. Then stoichiometrically you want to ensure that you have enough oxygen for all your carbon and (ideally) hydrogen, or you'll end up producing a lot of "unburnt" stuff which is inefficient. Notice that for each carbon in a linear hydrocarbon chain (-CH2-) you need 1.5 NO2 groups to get a complete reaction into CO2 and H2O. If you only have 1 NO2 group, CO2 will be formed and you will have excess H2 which is not combusted. Now as you say there are some stressed rings or cages that are hideously sensitive explosives, precisely because the hydrocarbon bonds have also had their stability reduced. But these typically are not practical explosives. For that you want the stuff to be a solid at a wide range of temperatures, you want it to be non-sensitive to friction and impact, and you want it to have a low vapor pressure. These are all details which depend strongly on the internal structure of the molecule.
- hoseja 5y ago
  I think most of their energy simply comes from the fact that diatomic nitrogen and carbon dioxide are very stable.
deleted 5y ago
[deleted]

dexwiz 5y ago

Yes, practically this means shoving as many nitro groups together. But what makes nitro groups explosive to begin with? From what I remember, the large electron shells of the oxygen atoms repel each other, increasing the bond N-O-N angle by a few degrees. It's very easy to break these stressed bonds, and oxidize another carbon compound with the liberated oxygen, creating CO2 gas (the explosive bit). Some of the most powerful explosives are made by attaching nitro groups to stressed ring or cage structures.

lmilcin 5y ago
Whenever I hear of "nitrogen stuffing" I remember https://blogs.sciencemag.org/pipeline/archives/2013/01/09/things_i_wont_work_with_azidoazide_azides_more_or_less https://blogs.sciencemag.org/pipeline/archives/2013/01/09/th...
- dexwiz 5y ago
  Haha! Perfect example of the "mouse trap".
  - lmilcin 5y ago
    Nothing that has 14 nitrogen atoms to only 2 other atoms in it can be considered a trap. It is bound to be exciting:) (see? "bound", haha, just barely)
semi-extrinsic 5y ago
Yeah, you are right that it's very easy to break apart nitro groups, but it's not much to do with the (O-N-O) bond angle. The bonds themselves in -NO2 groups are very weak, because nitrogen doesn't provide enough bonds to make things stable. Remember oxygen wants to "hold on with two hands" as we said in high school chemistry, that is to make a double bond or two single bonds. In NO2 each oxygen only gets one and a half bond (quantum mechanically it is in a superposition between having single bond to the first oxygen and double bond to the second, and vice versa). So this part becomes electronegative. Nitrogen, on the other hand, wants to have three bonds in total, but is forced to have four: 2x 1.5 to the oxygens, and one to the rest of the molecule. So this part becomes electropositive. Chemists will speak here of a resonance structure, which you can imagine is something that it is quite easy to excite. When the nitro group breaks apart, the nitrogen finds another nitrogen from another NO2 and forms N2 gas, which is highly stable due to its triple bond, so this part of the reaction releases a lot of energy and produces a lot of gas, and is very fast since it does not depend on any other sub-reactions. And stuffing lots of just nitrogen (without oxygen) into a molecule is in itself a way to make it very explosive - see azidotetrazolate salts. In NO2 decomposition, the oxygen then goes on to find carbon to make CO2, and hydrogen to make H2O, releasing more energy and producing more gas. But this first requires breaking down the relatively stable bonds in the hydrocarbon, so it actually consumes energy from the NO2 decompostion, before it releases more energy than it consumed. Then stoichiometrically you want to ensure that you have enough oxygen for all your carbon and (ideally) hydrogen, or you'll end up producing a lot of "unburnt" stuff which is inefficient. Notice that for each carbon in a linear hydrocarbon chain (-CH2-) you need 1.5 NO2 groups to get a complete reaction into CO2 and H2O. If you only have 1 NO2 group, CO2 will be formed and you will have excess H2 which is not combusted. Now as you say there are some stressed rings or cages that are hideously sensitive explosives, precisely because the hydrocarbon bonds have also had their stability reduced. But these typically are not practical explosives. For that you want the stuff to be a solid at a wide range of temperatures, you want it to be non-sensitive to friction and impact, and you want it to have a low vapor pressure. These are all details which depend strongly on the internal structure of the molecule.
hoseja 5y ago
I think most of their energy simply comes from the fact that diatomic nitrogen and carbon dioxide are very stable.

deleted 5y ago

[deleted]