“It is, of course, extremely toxic, but that’s the least of the problem. It is hypergolic [meaning it spontaneously ignites on contact] with every known fuel, and so rapidly hypergolic that no ignition delay has ever been measured. It is also hypergolic with such things as cloth, wood, and test engineers, not to mention asbestos, sand, and water — with which it reacts explosively.” - John D. Clark
The Nazis were going to use it as a combined incendiary weapon and poison gas!
With all apologies for the ClF3 hijack, here’s a little more from the rather enjoyable subsection, “Things I Won’t Work With”, of an organic chemist’s blog:
I chemist buddy of mine once said to me “Draino cracks me up. Wholesale cost of NaOH in 50-pounds bags is about 15 bucks.” This conversation occurred in the late 1980s. So for cost-effective mobster disposal, wouldn’t I be better off just using pure NaOH? After all, I’ve got a handy water supply right there. Any dental fillings, gallstones, Teflon implants, Legos, etc. can just be scraped up after the fact and thrown in the trash. You can’t get DNA off a Lego, so there’s no worries there. What is the wholesale cost of pure NaOH these days, anyway?
The thing that was never clear to me, although having never studied or taught highschool chemistry in the US I may well be utterly wrong, is why does Walt’s highschool chemistry lab have gallons of hydrofluoric acid?
I mean, in my late '80s, early '90s highschool chemistry lab we had one tiny bottle of the stuff, along with the other tiny bottles of high concentration nitric, sulphuric and hydrochloric acids all stored in a fume cupboard (there were lots of big bottles of various dilutions of those acids, except hydrofluoric). There were probably slightly larger bottles in the fume cupboard in the chemistry prep room to make up the dilutions, but that was it…it’s not like there’s an awful lot of call for hydrofluoric acid in GCSE and A-Level chemistry.
Until I read about chlorine trifluoride, I never knew that glass could actually ignite (HF can dissolve glass but it doesn’t burn)… Even materials that can withstand it can apparently only do so after treatment.
Also, as far as acids and alkalis go, alkalis often cause worse burns since they can more readily penetrate flesh because they don’t coagulate proteins (some acids like HF can, but HF burns are due more to fluoride toxicity, hence the delayed reaction, as stated in the description here; “hydrofluoric acid burns typically do not show visible evidence of injury for a day or two after exposure”).
