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Pretty simple (in theory that is) question for one of my worlds. I heard carbon fluorides are intense greenhouse gases but otherwise harmless and didn't lead to large issues (atleast none that I could forsee).

What natural process could cause these gases to be present in the atmosphere of a mostly Earth-like world with life?

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  • $\begingroup$ Well, the obvious answer would be "industry", but I assume you're looking for a natural explanation? $\endgroup$
    – Cadence
    Oct 3, 2019 at 1:40
  • $\begingroup$ @Cadence Well, the op did say "natural process" so that's probably a good assumption. $\endgroup$ Oct 3, 2019 at 2:09
  • $\begingroup$ Flurocarbons also deplete the ozone layer, so they're not just harmless other than being greenhouse gases. $\endgroup$
    – stix
    Oct 3, 2019 at 2:30
  • $\begingroup$ -1 for poor research. A 2-minute search for "naturally occurring fluorocarbons" found this document. See page 16. You're new to the site, Aezyc, please note that you are expected to perform research before asking a question here. $\endgroup$
    – JBH
    Oct 3, 2019 at 3:50
  • $\begingroup$ @JBH Your -1 is misplaced here. The article you cite discusses fluorochemistry in topical plants, and further research into it indicates that the handful of products that do exist are not the greenhouse gas variety of fluorocarbons, that is, tetrafluoromethane and hexafluoroethane. They are different forms of fluorocarbon compounds, such as fluoroacetatic acid, and thus would not be present in the atmosphere. Take a look: sciencedirect.com/science/article/pii/… $\endgroup$
    – Halfthawed
    Oct 3, 2019 at 14:19

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Fluorspar encased in graphite into lava might work under just the right circumstances.

Carbon fluorides form when carbon is exposed to fluorine gas at around 450 C. The problem is that this is more or less pure carbon and and pure fluorine gas. Carbon is very stable, even though fluorine isn't, which is why the high temperature is needed. There are two problems here. The first is fluorine gas. Fluorine gas is reactive. Very reactive, as in it's unstable to the point where I was under the impression that it cannot naturally occur. However, naturally, I was wrong. Small pockets of fluorine gas can exist in fluorspar (also known as fluorite) a mineral composed of mainly of CaF (Calcium Fluorite), but radioactive elements in impure fluorspar can lend electrons to Fluoride and allow it to form F2, fluorine gas, as long as it's in the fluorspar protected by the CaF around it. Then the trick is exposing it to carbon at 450-600 C. Lava will get us to the right temperature, and here's where we reach our second lucky break - graphite floats on magma. Graphite, that is, a mineral made of pure carbon, exactly what we're looking for.

So, imagine fluorspar encased in graphite, floating on 700 C magma. The graphite heats, reaches 450 degrees, and then reacts to the fluorine gas within the fluorspar, which hasn't melted because fluorspar has a melting point of 750 C. How it gets to the fluorine gas which is inside the fluorspar is unclear - perhaps a rock fell on the graphite, transferred the kinetic energy through the graphite to the fluorspar and cracked it open. Then another rock hits it, splitting it open and allowing the carbon fluoride to escape. A freak series of coincidences which naturally makes them present!

Is this possible? Yes. Likely? No, especially considering that this will yield a very small amount, most likely. If you try to replicate this under lab conditions, the yield would be a fraction of a fraction of what could be done. But it's still possible.

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    $\begingroup$ And once they're in the atmosphere, they are going to stay there instead of decomposing or being absorbed/adsorbed in significant quantity (inertness and insolubility in most other things), so they will accumulate on geological timescales $\endgroup$
    – Shalvenay
    Oct 4, 2019 at 3:07
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    $\begingroup$ Something that requires a ridiculously unlikely series of events that has the potential to maybe create a minute amount given an outrageous amount of luck is not going to accumulate in any significant amount in the atmosphere. $\endgroup$ Oct 4, 2019 at 23:08

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