Is there a type of acid (or some combination of an acid and something else) that can burn through glass?
Hydrofluoric acid will attack glass and a lot of other things; I think there are some plastics that can be used to contain it.
Yes, hydrofluoric acid (HF) is used to etch glass and will dissolve through any glass container you try to put it in. However, it can be kept in bottles made from polyethylene, polypropylene, Teflon, wax, lead or platinum.
It has a ferocious affinity for calcium, so if you spill any on yourself it will permeate through your skin, chomping away at your muscle and any soft tissue it comes into contact with, ausing irreversible damage. Then it will disslove your bones. Nasy stuff.
Calcium gluconate antidote gel is the only answer and it only works if you slap it on immediately after you spill HF on yourself and keep rubbing it in.
Thanks.
And gold too?
What’s so special about HF that HCl doesn’t have? Why doesn’t HCl eat through glass?
HF dissolves glass by leaching out the calcium ions in the glass. As glass is amorphous and has no crystalline strcture, it is mostly calcium, all higgeldy piggeldy, so the removal of the calcium by the HF to form CaF means that there is no remnant of any cage like crystalline structure, even if there were any other cations to jump into the spaces left by the calcium, the whole thing just disintegrates and there is no glass left.
It is to do with the atomic property of electronegativity.
All atoms have an inherant electronegativity value and the difference between electronegativity of atom A and the electonegativityof atom B determines how well they can get together and form a bond.
I see from this peroidic table here on my desk that the electronegativity of Cl 3.0, for F it’s 4.0 and for Ca it’s 1.0.
So a difference of 2, as for Cl and Ca is not at the level required to pull Ca out of the glass, whereas a difference of 3, as for F and Ca obviously is. I don’t know why, though. Sorry.
Not sure about Pt and Au. I’ll leave that to a metalurgist
(Passes the buck)
IANAM (or even a chemist), but these guys say gold’s OK for containment (and silver, nickel and a few special alloys). They also say that lead isn’t OK if the acid is too concentrated, but that HF is bulk shipped in aqueous solution.
I seem to recall that concentrated HCl does etch the surface of glass over time even though it’s generally safe to keep in glass containers.
I think you’re getting confused here. Glass is silica, SiO2 nominally. Calcium salts or maybe lime may be added to some kinds of glass, but it is not a major consituent.
Fluorine and silicon form a strong bond, and this is the driving force for the dissolution of glass by HF. The SiO2 becomes silicon tetrafluoride, SiF4, which is a gas.
Calcium salts and HF will form insoluble CaF2, as another poster mentioned, which is the basis for the “antidote” to the contact toxicity of HF. This doesn’t have to do with the dissolution of glass, though.
HF itself isn’t a strong acid (by the chemical definition) and it doesn’t attack gold or platinum like aqua regia does. The unique effect of HF on glass is a result of the fluoride ions as well as the fact that it’s an acid.
From everything I’ve read, HF poisoning is basically a recipe for a slow and painful death as it eats through your body and precipitates all your calcium ions as the fluoride salt. Result – nerves and muscles stop working.:eek:
Of course, in addition to HF, really good chili or really bad coffee will also do the trick. 
Good grief, of course you’re right. I was reading something about Ca when I posted. Silly me.
Sorry about that.
Thanks for pointing it out without making me look like too much of a nitwit, JHW
I have first hand experience (literally), being a) stupid and b) a chemist.
HF is perfectly well contained in any plastic container.
It does react with glass but it’s not very exciting to watch, just a rather slow etching.
Whe you get it on your skin, it does burn, but it doesn’t rapidly burn right through your skin. It is painful, the gel does work, but the main issue is that it takes forever for the burn to heal. Well, weeks anyway.