Yeah – sorry about that. “Mental Rolodex got stuck”, as Pepper Mill says.
In principle, you’d think that silicone chains/siloxane compounds (as suggested above) could fill the bill. The problem is that virtually all of the commercial ones are organo-silanes, with methyl and ethyl groups sticking oyut the sides. I can’t find anything to corroborate that an -Si-O-Si-O- backbone saturated with hydrogens or halogens would be inoffensive (although, again, I suspect so). A short enough chain polymer of this sort ought to be liquid (although that, too, isn’t clear. short-chain polytetrafluorine isn’t, although polychlorotrifluoroethylene is).
I think the answer you seek is very simple. Most inorganic substances are happy and stable as ions. Ions form ionic lattices and are not liquids except at high temperature. Hence most inorganic substances that are not ionic (and therefore possibly liquid) are going to be reactive.
as well, almost all non ionic bonds tend to be reactive, with the exception of group IV - carbon and silicon especially (and some B). Only C forms kinetically stable bonds to H and Cl and O, and this enables small molecules to be easily made. Silicon and B ends up making polymers as they find it hard to find a stable monofunctional stopping group.
1: Most chemicals are organic.
2: Few chemicals are liquid at STP.
3: Of those few chemicals which are liquid at STP, most are reactive.
So in looking for safe inorganic liquids, you’re taking a small subset of a small subset of a small subset. But then you’re surprised when there isn’t much left. You’ve yet to demonstrate that a higher proportion of inorganic liquids are dangerous than of organic liquids. Yes, there are only a handful of examples (such as water) for the inorganics, but then, there aren’t that many inorganics to begin with. Are you sure that the abundance of safe organics isn’t just due to the abundance of organics, period?
scm – thanks. That’s the best answer I’ve come across.
I’ve just looked up siloxanes. There don’t seem to be any siloxanes that don’t have organic functional groups hanging off the silicon-oxygen backbone. Not merely commercially, but also in chemical catalogs, technical papers, and the Kirk-Othmer encyclopedia. I suspect that, if they existed, they’d be in one of these places. If stable, somebody would be using them for something. This makes me suspect that completely inorganic silicones on’t exist, and all we have are organo-silicones.
Small I can understand. But, with the exception of water (and maybe some of the hypotheticals I’ve listed), this small-small-small subset is a null set. That’s what bugs me. Scm’s explanation might be the appropriate one.
Love the entry on arsole, but it’s just rotten with carbons and C-H bonds. Somebody has too much time on their hands, clearly.
On a lighter note, it turns out that borazine is a liquid at room temperature and relatively benign. The null set may have increased by one (and possibly more – there are related compounds).
In other words, certain elements are inorganic because they are dangerous – they are not dangerous because they’re inorganic.
Molecules with “inorganic” elements tend to have very special reactivity – for instance, most transition metals will rapidly make stable, insoluble complexes with thiols in proteins. That’s why we don’t have transition metals (in appreciable quantities, except for maybe iron) in our bodies to begin with, and when they’re there, they’re carefully regulated (ferritin, heme, etc).
Organic molecules have evolved (or were created :rolleyes: ) to be very unreactive, specifically so that very few chemical reactions can occur without enzyme catalysis – this allows a cell to control the level of reaction that occurs, and to create mechanisms to stop malfunction. Throwing in any sort of reactive compounds, whether they’re heavy metals, alkyl halogens, or formaldehyde (organic!), tends to produce all sorts of unwanted chemical reactions which lead to cell death.
It doesn’t quite meet the technical definition of “standard room temperature”, but where I come from temperatures of 85-90 F are common enough that I’d consider Gallium a liquid.
“Gallium is used in some high temperature thermometers, and a eutectic alloy of gallium, indium, and tin is widely available in fever thermometers, replacing mercury. This alloy, with the trade name Galinstan, has a freezing point of −20 °C.”
so add another (relatively) nontoxic inorganic liquid
Well, iodine melts at 113.5 degrees C, so it’s not a liquid at temperatures I’d want to be around.
The tincture of iodine used as treatment for cuts is a solution of iodine dissolved in alcohol, which is pretty organic.
You answered your own question. Unless you’re someplace where it’s hot, mercury and bromine are the only two elemental liquids at room temperature. I discounted mercury because of its toxic properties (although it’s not immediately so. Leave it in, if you want), but bromine not only gives off noxious vapors, it’s also pretty reactive. YMMV, but I don’t want to sit around it.
