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In what we usually consider combustion your fuel and oxidizer are always neutral, but is it possible to have a similar "explosive" combustion process where both the fuel and oxidizer have been singly ionized? If so what might some potential fuels be, and where might more information on the topic be found? A google search doesn't turn up much (other than injecting a small amount of plasma to catalyze an otherwise non-ionized reaction.)

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  • $\begingroup$ I'm afraid that this time that the google search doesn't turn up much has good reasons - do you understand what combustion is? $\endgroup$ – Mithoron Feb 18 '15 at 23:02
  • $\begingroup$ Well chemistry isn't exactly my specialty which is why I'm asking, but as far as I understand combustion is just an interaction between valance electrons which result in new molecules that want to expand.. ionized molecules will feel coulomb repulsion however if they're compressed together I don't see any reason they wouldn't be able to react. $\endgroup$ – AltusVultur Feb 18 '15 at 23:36
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If you specifically mean a hot plasma, I think it might be possible but it's a tough request. To get combustion, you'll need to start off with form of bonding present between atoms in the plasma. This requires finding a molecule with atoms so strongly bound that the bond dissociation energy is higher than the molecule's ionization energy.

Given that the lowest ionization energy known (3.51 eV or about 340 kJ/mol for ditungsten tetra(hpp)) is comparable to relatively sturdy covalent single bonds, there's not much room for negotiation. Ionization energies easily become larger than even strong covalent double bond dissociation energies, so there's a large tendency for any substance to be stripped into its constituent atoms before getting a chance to ionize.

The situation is easier if you allow the usage of "cold" plasmas. Plasma generators are commonly used to scour surfaces completely clean of any organic residues. I don't see why you couldn't just insert oxygen and some organic gas into such a generator, ionize them both with the strong and rapidly varying electric field inside, and cause the organic gas to combust.

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In a practical sense, the answer is No.

The reason is that a substance reaching a plasma stage is ionized to a point where there is not opportunity to interact with another substance (in the case of combustion by definition Oxygen to produce water and CO2).

Only after the matter de-ionized follows the returns to a natural substance which can undergo combustion. But by the time this happens, the substance may undergo combustion but is no longer in plasma phase.

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  • $\begingroup$ Could lightning be combusted ?! $\endgroup$ – Technetium Dec 17 '16 at 0:48
  • $\begingroup$ The term lighting describes a spontaneous and violent discharge of electrons from one place to another. (This is what you see in a thunderstorm). There is no matter undergoing a chemical reaction with Oxygen. The term combustion applies when a chemical undergoes a oxidation reaction with Oxygen. Therefore, a lighting is not a phenomenon that may undergo a combustion. $\endgroup$ – Jose Enrique Calderon Dec 18 '16 at 5:58

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