Ok, so I have an inhabited planet that has a moderately chlorinated atmosphere (7% chorine), and with oceans that are composed of a water/ammonia mix. the temperature is very cold, -50 C. I am wondering if this world can exist.

  • $\begingroup$ Plausible in what sense? Evolve how? $\endgroup$
    – Joachim
    Nov 25, 2022 at 19:12

1 Answer 1


Your ammonia will want to eat up your chlorine.


2NH3 + 3Cl2 = N2 + 6HCl

NH3 + HCl = NH4Cl

First the chlorine will take hydrogen from the ammonia and make HCl which will dissolve in your oceans as the acid. N and N are united as they love to be and they will not appear in the story after that.

HCl will find another NH3 and make ammonium chloride. That will stay in the water.

Maybe if you have some autotroph and external energy source you can have that regenerate the Cl2 from the ammonium chloride? I have to think they would keep the Cl2 in their tissues somehow because that is where the energy is stored and if those plant analogs let it go into the atmosphere I dont see what they get out of the arrangement.

The extreme cold makes this more interesting. The reactions might take place just on the surface of the frozen ocean, with a layer of solid ammonium chloride then protecting the ammonia / water below.

  • $\begingroup$ What a nightmarish surface. $\endgroup$
    – user71781
    Nov 25, 2022 at 20:20
  • $\begingroup$ I was thinking this world was like earth during the great oxidation event, but instead of oxygen, it is chorine. $\endgroup$ Nov 26, 2022 at 4:41
  • $\begingroup$ @RickGennings - I have considered a salty world where autotrophs use a photosynthesis analog to split the Na and Cl. The autotrophs release Cl as gas - your great oxidation. They keep the Na in their bodies as sored energy like plants do with glucose - to be later turned into energy by reacting it with Cl2 and regenerating NaCl. $\endgroup$
    – Willk
    Nov 26, 2022 at 16:21

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