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It is a cruel irony of Earth that our atmosphere is made up of such an odd mixture. It’s odd to think that air itself is outright dangerous. Four fifths of th

It is a cruel irony of Earth that our atmosphere is made up of such an odd mixture. It’s odd to think that air itself is outright dangerous. Four fifths of the fluid in which we live and breath ranges from inert to noble. The remaining fifth is one of the most dangerous, angry, reactive, poisonous gasses we know: Oxygen. It is crucial to life and yet at the same time is quite capable of partially or completely destroying everything we hold dear. Our tools, belongings, us, our homes, warships, forests, crops and savannahs. It needn’t even burn with a flame: most things will decay in its presence with or without spectacle. If one encountered a planet where almost everything was made of gelatinous gasoline, whose principle inhabitants were a form of highly evolved sentient matchstick that kept striking boards as pets, one might think them a little risk averse. Then of course you’d realize that life and society on this planet have evolved in such a way because they are neither unfortunate or insane enough to live on a world that’s blanketed in O₂. On a visit to this planet you explain to their ambassador about the atmosphere on your home world. She doesn’t know whether to laugh hysterically or faint in horror. The knowledge terrifies her and she takes deep methane breaths while stroking her phosphorous hands on tibbles-the-striking-board, trying to calm down. You decide it’s best not to further disturb her with stories of plate tectonics and the major cities, nuclear reactors, etc your people have built on fault lines, at sea level.

rckoepke 6y ago
> One fifth is the most dangerous, angry, reactive, poisonous gas we know. Obviously you're utilizing hyperbole here, but I'm assuming you're referring to oxygen's oxidative potential (really "standard reduction potential"), but other gases have significantly higher reduction potentials than oxygen. Fluorine and Chlorine cause bigger, hotter fires at conditions that would generally be considered "non-flammable" if oxygen were involved instead. They also corrode/rust things faster than oxygen does. Charts like [0] are misleading because they list the standard reduction potential of the monoatomic forms, which isn't realistic when most of these form diatomic gases (e.g. Cl2, O2, etc). Both fluorine and chlorine gases are more oxidative than oxygen. Chlorine has electron affinity of -2.4 eV and while O2 is -0.4 eV. 0: https://www.angelo.edu/faculty/kboudrea/periodic/trends_electronegativity.htm https://www.angelo.edu/faculty/kboudrea/periodic/trends_elec...
- gorgoiler 6y ago
  It would indeed be an even crazier planet where those gasses were part of the atmosphere and our lives! (Also, hyperbole clarified.)
- Reelin 6y ago
  > at conditions that would generally be considered "non-flammable" if oxygen were involved instead "Generally considered non-flammable" doesn't even begin to describe it. From (http://www.lateralscience.co.uk/Fluorine/Fluorine.html http://www.lateralscience.co.uk/Fluorine/Fluorine.html): > the problem was its collection and containment. Fluorine chemically reacts with just about everything, usually very vigorously. He fashioned collection vials from platinum, palladium and gold. All were destroyed. As to the GP: > > the most dangerous, angry, reactive, poisonous gas we know To continue the nitpicking, bear in mind that a gas is just one phase of matter for a particular chemical. What we're really after then is something from among the most reactive chemicals we know. I nominate dioxygen difluoride which will (for example) react with liquid methane at -180C. It's antics are summarized by Derek Lowe. (https://blogs.sciencemag.org/pipeline/archives/2010/02/23/things_i_wont_work_with_dioxygen_difluoride https://blogs.sciencemag.org/pipeline/archives/2010/02/23/th...)

rckoepke 6y ago

> One fifth is the most dangerous, angry, reactive, poisonous gas we know. Obviously you're utilizing hyperbole here, but I'm assuming you're referring to oxygen's oxidative potential (really "standard reduction potential"), but other gases have significantly higher reduction potentials than oxygen. Fluorine and Chlorine cause bigger, hotter fires at conditions that would generally be considered "non-flammable" if oxygen were involved instead. They also corrode/rust things faster than oxygen does. Charts like [0] are misleading because they list the standard reduction potential of the monoatomic forms, which isn't realistic when most of these form diatomic gases (e.g. Cl2, O2, etc). Both fluorine and chlorine gases are more oxidative than oxygen. Chlorine has electron affinity of -2.4 eV and while O2 is -0.4 eV. 0: https://www.angelo.edu/faculty/kboudrea/periodic/trends_electronegativity.htm https://www.angelo.edu/faculty/kboudrea/periodic/trends_elec...

gorgoiler 6y ago
It would indeed be an even crazier planet where those gasses were part of the atmosphere and our lives! (Also, hyperbole clarified.)
Reelin 6y ago
> at conditions that would generally be considered "non-flammable" if oxygen were involved instead "Generally considered non-flammable" doesn't even begin to describe it. From (http://www.lateralscience.co.uk/Fluorine/Fluorine.html http://www.lateralscience.co.uk/Fluorine/Fluorine.html): > the problem was its collection and containment. Fluorine chemically reacts with just about everything, usually very vigorously. He fashioned collection vials from platinum, palladium and gold. All were destroyed. As to the GP: > > the most dangerous, angry, reactive, poisonous gas we know To continue the nitpicking, bear in mind that a gas is just one phase of matter for a particular chemical. What we're really after then is something from among the most reactive chemicals we know. I nominate dioxygen difluoride which will (for example) react with liquid methane at -180C. It's antics are summarized by Derek Lowe. (https://blogs.sciencemag.org/pipeline/archives/2010/02/23/things_i_wont_work_with_dioxygen_difluoride https://blogs.sciencemag.org/pipeline/archives/2010/02/23/th...)