I've seen all of the silicon based stuff, but those require high temperatures. I am planning on doing something in a cold area, where I wanted a character to be silicon based. I learned that you need high temperatures for that, so, I did some research, and found an alternative: Silane. I found an answer on here by Logan R. Kearsley, but I never knew about this site beforehand and cannot comment to ask for clarification. I've done a lot of research and can't find anything about silane stuff. I might even be reading it wrong, but what I understand is that silane based silicon life would need a cold environment, drink ammonium hydroxide, and breath(but not exhale) hydrogen. That isn't a lot for me. How does silane play a role in their bodies? How would silane-based silicon life work, and what differences would it have from silicone-based silicon life?
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$\begingroup$ Polysilanes are the silicon analogues of hydrocarbons. Unfortunately, silicon-silicon bonds are very much weaker than carbon-carbon bonds, so that the chemistry of polysilanes is enormously poorer than the chemistry of hydrocarbons. Beyond disilane and trisilane, polysilanes with no silicon-carbon bonds, which would be the direct analogue of hydrocarbons, are rather ephemeral so that little is known about them; this is why you did not find much. $\endgroup$– AlexPCommented Apr 28 at 23:58
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1$\begingroup$ In the last word of the title, do you mean silicon or silicone? $\endgroup$– L.Dutch ♦Commented Apr 29 at 5:12
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$\begingroup$ @L.Dutch: When fantasizing about silicon-based life, the usual approach is to imagine that the chemistry of life is based around compounds with a silicone chain, ···—Si—O—Si—O—···, backbone. Unlike carbon chains ···—C—C—··· on which our organic chemistry is based, silicon chains ···—Si—Si—··· don't really work all that well, at least not in conditions which would be readily accessible to Earth chemists. The question is asking whether such silicon chains would work in some exotic conditions. $\endgroup$– AlexPCommented Apr 29 at 7:51
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$\begingroup$ Hello @484is22squared. Please keep in mind that Stack Exchange is designed to address one problem at a time and those problems are expected to be narrowly defined, quantifiable, and answerable without writing a complete text book. You're asking multiple questions and they're really broad. For example "how would silane-based silicon life work?" is way beyond what SE is intended to do. $\endgroup$– JBHCommented Apr 29 at 18:49
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$\begingroup$ @JBH oh sorry about that, I see how this site works now lol, thanks. I will make a new question that is more direct. $\endgroup$– 484is22squaredCommented Apr 30 at 7:47
2 Answers
what I understand is that silane based silicon life would need a cold environment, drink ammonium hydroxide, and breath(but not exhale) hydrogen.
That won't work. In the presence of hydroxide ions, silane will react to produce silicic acid. That's how strong bases like ammonium hydroxide dissolve both silanes and silicones / silica crystals: they convert SiO2 into Si(OH)4 through exchange reactions, and SIH4 into Si(OH)4 + 2H2 through oxidation reactions.
Pure polysilanes won't dissolve in polar solvents just like pure hydrocarbons don't. Our biochemistry dissolves carbon chains by adding polar groups to them, producing amino acids (added nitrogen centers), carbohydrates (added oxygens and hydroxyls), and phospholipids (added phosphate groups). You could maybe have silane-based in mostly-pure ammonia, or in a (much colder) non-polar cryosolvent like liquid argon or nitrogen--although, to be honest, those aren't really great solvents. There just aren't that many cryosolvents that don't contain carbon. OF2 could work, but where are you going to get enough of it? And if you've got large amounts of carbonaceous cryosolvents, why are you using silicon chains for biology? A mixed carbon-silicon biology might work, exploiting the reactivity of silicon to make up for the reduced reactivity of carbon at low temperatures. But if you really want silane-dominated life, you've got to minimize carbon in the environment.
So, through out the water, you've just got pure ammonia. Now, autotrophs would consume silane gas and ammonia to produce complex siloaminate compounds, releasing excess hydrogen, and heterotrophs would breathe in hydrogen and use it to reduce biomolecules back to liquid ammonia and silanol gas. This is exactly analogous to the hydrogen-breathing carbon-based metabolims, where autotrophs consume water and methane to produce carbohydrates and lipids, and heterotrophs consume hydrogen and release methane and water. (This is a very rare cycle on Earth, but it's what methanogenic bacteria do.)
If you go much colder than ammonia, you can probably justify (liquid) oxygen-breathing silane-based biochemistry. This would be more like the aerobic life we are familiar with on Earth, but not exactly the same since SiO2, unlike CO2, is not a gas: autotrophs consume simple silicic polymers (breaking down rocks for silicon dioxide, using waste silico-organic materials like amorphous silicic acid) and release oxygen; heterotrophs breathe oxygen, and, if they are small enough, excrete silicon dioxide crystals. That's difficult to manage for complex lifeforms, so you might expect multicellular animals to handle their waste silicon the same way we handle our waste nitrogen: not by breaking it down to its simplest form to get all the energy possible out of it, because the end products are Not Good for our cellular environment, but rather packaging it up in a low-ish energy molecule (i.e., urea, silici acid) that is easier to transport out of the body. You get the same waste-transport complications with oxygen-breathing polysilicone-based life.
In my own project, I justified the existence of complex life at a low enough temperature (i.e., low enough that polysilane-rich cells wouldn't spontaneously combust) to breathe liquid oxygen despite the low solvation capacity of abundant cryosolvents (like liquid nitrogen) by positing that early polysilane-based life figured out how to construct mixed-hydrocarbon cryosolvents to facilitate intracellular reactions, rather like how we use relatively low-abundance phosphorus for so much of our energy metabolism (and in our genertic molecules).
Silicon-based life forms that rely on silane (SiH4) for biochemical processes instead of high-temperature silicon-oxygen compounds could potentially thrive in cold environments. In these organisms, silane would play a similar role to hydrocarbons in Earth's life forms, serving as the foundation for organic-like molecules. These life forms would likely consume ammonium hydroxide, which can dissolve silanes and facilitate metabolic reactions, while relying on hydrogen for their biochemical processes. Unlike silicone-based life, which requires high temperatures, silane-based life would operate at lower temperatures due to the stability and reactivity of silane compounds in cold conditions. This metabolic process would involve the utilization of silane compounds for both energy production and structural functions, presenting a stark contrast to the oxygen and silicon chemistry of high-temperature silicon-based life.