Dangerous Inorganic Liquids

Factual Questions
1

I was looking at inorganic substances that are liquid at ordinary temperature and pressure, and I’m struck by how incredibly dangerous they are. If you except halogenated hydrocarbons and their polymers – many of which, like Teflon, are amazingly benign, but some of which, like carbon tetrachloride, are toxic and carcinogenic – just about all the rest are not merely dangerous, but spectacularly dangerous. They’re not merely reactive, but corrosive, not merely energetic, but explosive. They don’t just react with water, they react violently. They’re highly flammable, and sometimes excruciatingly stenchy.
All the ocychlorides are dangerous. They cause blistering and can cause edema if you inhale them. A spill of 2 milliliters (that’s the amount in one of those teeny containers of Crazy Glue) once caused the evacuation of a building.

Carbon disulfide is incredibly flammable and incredibly stinky. Ratchet it up by one on the periodic table and you get cadmium sulfide, whose stench is sickness-inducing. A spill of cad sulfide once caused the evacuation of an entire town in Germany. An inorganic chemist put it on his website of Things I Won’t Work With. Tellurium compounds are worse.

Most others seem to be explosive. The liquids fume when first made, reacting with water vapor in the air.

Mercury is the most benign that I’ve found – but even mercury will eventually kill you. Nobody wants to be anywhere near free mercury, and they call out the toxic waste squads if they find any.

the old science fiction canard about silicon-based life (because silicon, one step down in the periodic table from carbon, is so similar to carbon chemically) doesn’t pan out. You don’t want to get any silicon-based analogies to hydrocarbons that are liquid at room temperature anmywhere near water. They’ll react or explode.

I mentioned this to some people, and they said that was just selecting my cases. But I’m not. Aside from the halogenated compounds notred above, every single inorganic liquid at room temperature is pretty damned nasty.
Why? I could understand if 90% of chemicals were dangerous, or even 95%. But it’s well over 99%, from what I can find, that are simply too dangerous to want to be around. This isn’t the case with hydrocarbons =-- I can spend time with the alcohols. They’re flammable, but not deadly. Toluene, acetone, other random liquids. The esters are flavorings, and generally smel pretty good. Oils of all kinds are benign.

So why are inorganics so dangerous?

2

Obligatory dihydrogen monoxide link

It’s often easier to get things to react if one substance in the gas or liquid phase, so I would expect inorganic liquids to be far more reactive on average than solids.

I guess that most of the inorganic solids on earth are also hazardous when liquid, but that’s because they’re often lava :smiley:

As far as elements go, mercury is not the worst as far as toxicity is concerned (I think Plutonium is, but that may not count since it tends to be man-made.) There are a few other liquid elements (especially if we allow for a broader room temperature range.) I’m not sure how bad they are.

Also keep in mind that our atmosphere contains dioxygen, which is a very reactive molecule. In order to make something that is unreactive to it you often have to have very strong internal bonding, which tends to lead to a solid at STP. Granted there are plenty of unreactive liquids and reactive solids; this is just a general rule that I just made up now and it could be wrong.

I’ve said that liquids tend to be more reactive than solids, but what about organics? I have to go to work now to play with some organic liquids and solids. I’ll think about this until later.

3

My point about mercury is that it was about the most benign of the inorganic liquids. I included it because there are only two liquid elements at STP. The other is bromine – highly reactive, fuming. Not benign. And mercury is now so scary that people immediately put on protective gear to pick it up.
I’m not saying there aren’t dangerous inorganic liquids – there are plenty of tem, with problems of all sorts. But there are plenty of momaqueous organi liquids that I wouldn’t mind sitting around an open dish of. Methyl Salicylate smells wonderful. You don’t want to drink it, but that’s OK. I used to work with toluene-reeling model cement all the time. Alcohols don’t bother me at all. Planty of cleaning solvents are fine.

But find me just one inorganic liquid that isn’t a halogenated hydrocarbon)that you’d feel safe sitting around an open dish of.

4

Ummm… how about good old dihydrogen monoxide?? :smiley: I know, people have written up scare tracts about the stuff, but it isn’t as unsafe as all that!
[sub]hehe[/sub]

5

Yeah.

You people keep saying “water” 'cause you can’t think of anything else.

I could make a case that water is really the simplest possible alcohol – it’s just missing that carbon atom. it certainly fits in the sequence that it’s not obviously part of. Kinda like 0[sup]0[/sup].
So what inorganic liquid besides halogenated hydrocarbons and water wouldn’t you mind spending time in a room that had a dish full of it? I still can’t find any.

6

Hmmm. I was playing with a bottle of conc sulfuric acid today. Not exactly safe but I wasn’t calling the men with rubber bodysuits and high tech clean up gear when a drop landed on the bench.

My best shot at an answer: We are carbon based life forms. Our bodies are designed to cope with the types of bonds and reaction rates that are common with carbon atoms. As soon as you move into the realm of inorganic you are going to get conditions that are hazardous for us. Granted, you get some pretty benign stuff too – witness the average rock. But liquids have a certain molecular motility and accompanying reaction rates and that just isn’t a good situation for the average body part.

7

We people?? I didn’t notice anyone else talking about water. And I’m not really trying to poke a hole in your case. You asked for one liquid. I jumped in to supply one. (And if you can think of a way of describing the alcohols sequence so that it obviously includes water, go ahead. You mentioned hydrocarbons, which water is definitely NOT on account of having no carbon.)

[chris walks away, whistling idly.]

8

Then you obviously didn’t look at Ruken’s reply.

Nyah Nyah. You still didn’t come up with anything besides water.

And j-sum – I’ve worked with all sorts of acids, including concentrated sulfuric, but they all contain some water.

9

H(CH[sub]2[/sub])[sub]n[/sub]OH, where n=0 :stuck_out_tongue:

10

I think we have a terminology problem. You asked for inorganic liquids - yet most of the examples discussed so far are classed as organic compounds. Quite a few contain “inorganic” atoms so the line is often blurry. There is also a question on what harmful means - almost all organic and inorganic chemicals are harmful to some degree. Some are corrosive, some toxic, and some cause long term but not chronic problems.

There are many essentially “inorganic” nonharmful liquids. Siloxanes spring to mind. They were used in breast implants.
“Ionic liquids” (try googling) often contain metal compounds and are usually relatively benign. While I wouldnt swallow them they are fairly safe.

You are right in one degree. Liquids are often trickier to handle because they tend to be more reactive than an equivalent solid. That is because the molecules are free to move and react instead of being locked up in the solid.

11

Right – no one’s giving me inorganic examples.
I’d classify inorganic as not containing C- H bonds (and I’m including C - D. You can’t dodge out of this by using deuterium – it’s still hydrogen). I’ll allow carbon disulfide as inorganic. I’ve already disqualified halogenated hydrocarbons – they seem to be the only safe class I’ve found. I’d also like to disqualify acids – HF and HCl and so forth are always in aqueous solutions. The ones with little water are often fuming. The really harmless acids are pretty obviously organic (like the fatty acids they make soap from).

as for dangerous – I’ve pretty much said what I mean – what wouldn’t you mind being in an enclosed space with an open dish of the stuff.

The ionic liquids a.) usually require elevated temperatures and b.) are organic. They don’t meet two criteria.

They used silicones in breast implants. And silicones and siloxanes all ciontain organic methyl groups and the like.

You still haven’t come up with a wholly inorganic safe liquid at room temperature.

12

Cal, go buy a chemistry book, read up on the chemical definition of “organic,” and then quit freakin’ posting about inorganic hydrocarbons, 'K? 'cause I can’t figure out what the hell class of compounds you think you’re eliminating when you insist on limiting the discussion to inorganic compounds.

13

It’s pretty clear – I mean those without hydrocrabon chains , even in added functional groups. The Wikipedia definition is:

All the “safe” things people keep bringing up have methyl groups or the like. I’m looking for something without any of those. And I’m eliminating the halogenated hydrocarbons because they’re pretty damned similar to the ordinary hydrocarbons. Maybe it’s that carbon chain that makes things inoffensive p0-- I don’t know.

If you restrict yourself to things that contain no casrbon or hydrogen you’ll be in the class of compounds I’m looking at. (You’ll also eliminate things like carbon disulfide, which are in pretty much everyone’s definition of inorganic, but I can live with that).

So why is it that things like

SbCl5
BrF3
Cl2O7
Ga2H8
H2Bi
IF3
PbCl4
SeF4
AsF3
BBr2I
NOCl
PCl2

etc.
Virtually everything that you find by running down the entries in your CRC Handbook section on Inorganic chemicals is pyrophioric, carcinogenic, highly toxic, or explosive? I wouldn’t want to sit in an enclosed room withb any of these. But a random selection of organic chemicvals would probably contain at least one substance that’s pretty benign.

14

How about 1-n-butyl-3-methylimidazolium tetrafluoroborate or 1-n-butyl-3-methylimidazolium hexafluorophosphate? Not to mention a 1:1 mixture of triethylammonium chloride and cooper chloride (that is cooper chloride, and not copper chloride!). OK, the first two can probably be considered more organic than inorganic, but they are so-called ionic liquids, or “molten salts”, so the distinction is hard to make. The third suggestion is completely anorganic and melts at 25° C, so I guess it might just count.

I admit, I’m a Chemical Engineer and I couldn’t think of anything until I remembered some colleagues who once worked on ionic liquids as solvents for organic reactions.

15

Interesting – what the heck is “cooper chloride”?

Of course, it’s got that “ethyl-” in it…

16

I’m not sure what you want us to say here. IAAChemist and I’m not exactly sure what you are trying to prove here. The reason there is a higher proportion of benign organics is because WE’RE organic. Not just our bodies, but the entire nature of life is predicated on carbon-based compounds; we’re build of carbon chains and we are built to consume carbon (yes and the rest of CHNOps, etc). Given a list of 100 organic compounds, sure you might find one that is relatively benign. Still there are an immense amount of organic compounds, and to assume that a significant proportion is benign is borderline ridiculous. Some are explosive (picric acid, TriNitroToluene, etc). Some are carcinogenic. Some are good in small doses but a large amount will wreak havoc (most hormones, for example).

If that doesn’t satisfy you, think of WHY carbon-based is not just the majority system, but the ONLY system of life as we know it. Carbon is tetravalent, so it will be capable of forming many complex compounds. But more important is the stability. Carbon tends to form very stable bonds with other important elements such as nitrogen and oxygen; even incredibly reactive phosphorous will form relatively stable bonds with carbon.

The fact that many inorganic compounds are liquid is just a function of chemical bonds and periodicity within the elements. The liquid state of inorganics is not inherantly “more dangerous” or whatever than the gaseous or solid state. I wouldn’t want to be around solid ammonium nitrate any more than i would want to be around liquid BrF3 or gaseous HCl.

In short, if you’re looking for some special reason why inorganic liquids are dangerous, there’s no answer that’ll appease you. It is merely a function of what are bodies are equipped to handle. Perhaps there’s some planet with lifeforms who aren’t bothered by dimethylmercury or dihydrogen sulfide, but that means nothing to us. Organic liquids are on the whole just as problematic for our bodies as inorganic liquids–the only difference is that every now and then we will have some way to process the organic one because it is similar to some other biological molecule, an option not available for most inorganics.

17

I just checked again, and it’s a typo after all (not strange considering the authors are Brazilian, but the article was published in English), it should be copper chloride, and except for those three ethyl groups, that mix is pretty inorganic.

18

There is one class of materials that might meet my criteria. The problem is that I haven’t been able to find out how dangerous they are, if at all.

The representative compound is Borazole, aka Borazine, with formula B[sub]3[/sub]N[sub]e[/sub]H[sub]6[/sub]. It’s physically similar to Benzene, with alternating borons and nitrogens taking the places of the carbons. The bond lengths are almost precisely the same, and it has the same bond resonance as benzene. There are other cyclic boron-nitrogen analogues of carbon compounds as well.

There are works proclaiming this “inorganic benzene” and others claiming that it’s not inorganic benzene – it’s not technically “aromatic”, the electron localization is al wrong, etc.

Nevertheless, it’s close enough for me, even if it turns out to be as toxic and carcinogenic as benzene. At least it’s not as bad as those other inorganics. It would be on a level with carbon tet.

The problem is, nothing 've come across tells me just how dangerous it is. For all i know, it could be as bad as the rest of them, although I’d guess that it wasn’t. I could even get around my self0imposed ban on hydrogens if I halogenate it.

as for what I am trying to prove, I’m not trying to prove anything. But the lack of stable inorganic liquids on earth seems particularly noteworthy to me (all those others – tetrafluoroethtylene and tribromochloromethane and others are artificial, manmade). Why in hell do liquids have to be either water or organic in order to exist freely? I think it’s a question of somer validity, and “It’s all because of the bond strengths” seems inadequate as an answer. There are plenty of stable inorganic solids and gases. Why not liquids?

19

Cadmium sulfide’s not a liquid. It’s a rock. And it’s odorless, or so sayeth Google.

20

Okay, I figured it out. When you said “ratchet [carbon disulfide] up by one”, you meant “carbon diselenide”. I was trying to figure out what you were getting at, since cadmium’s way lower on the periodic chart than carbon and sulfer. Doozy of a spelling error you made, though.