Wednesday, July 11, 2012

Hey, Who’s Up for Sniffing Some Elemental Flourine?

This guy, apparently.

Via Katharine Sanderson at
Fluorine gas is so reactive that any naturally-occurring whiffs cannot exist for more than a few fleeting seconds. At least, that has been the conventional wisdom for more than a century.

Now, chemists have proved that a smelly rock is the only known place on Earth where fluorine exists in its elemental form, F2.

The rock is antozonite, a calcium fluoride (fluorite) mineral that is dark violet or even black in colour, also known as fetid fluorite or stinkspar. Needless to say, this rock stinks. The pungent smell is given off when antozonite is crushed, and chemists and mineralogists have argued over the origin of the stench since the early nineteenth century.

[Dr. Florian Kraus’s] first task was to smell the crushed rock — and he immediately recognized the stench: “A fluorine chemist knows at once how fluorine smells,” he says.
OK, but that’s not so helpful to the rest of us.

From the opening lines of the paper:
Elemental fluorine, F2, is the most reactive chemical element. Great experimental skill and special equipment are necessary to handle it safely.
So Kraus does what any rational scientist would do . . . he inhales some!
We compared the smell of crushed “antozonite” directly with authentic F2 gas and unambiguously confirmed that the odor of the mineral corresponds to F2. The smell of F2 is decisively different from that of O3, Cl2, HOF, HF, OF2, and XeF2, which were also smelled in direct comparison. [Dude!—Ed.]
We look forward to muddling some antozonite into our next mojito. So what if there is a little uranium or thorium in it? That’s what gives you the five-hour energy!

The article discussed here is "Occurrence of difluorine F2 in nature—in situ proof and quantification by NMR spectroscopy,” by Jörn Schmedt auf der Günne, Martin Mangstl, and Florian Kraus, which appeared in Angewandte Chemie International Edition, July 4, 2012.


EdC said...

I understand the original statement to mean that F2 would react with and destroy any olfactory receptor it encountered. Is there any explanation for why that's not so?

Avery Gilbert said...


It had me wondering about possible adverse consequences too.

Here's a spooky thought: Is there a molecule so chemically destructive to your nasal epithelium that you smell it once and then you can never smell anything again?

Anonymous said...

First thing any budding fluorine chemist should do is get to know what it smells like (kind of like chlorine, but sharper).

In VERY VERY dilute concentrations, it does not kill you or prevent you from smelling again. Too large of a whiff can have SEVERE consequences though.

Avery Gilbert said...


Good to know!

I mean about "like chlorine, but sharper."

Unknown said...

Sharper is a good way to put it, I also described as a sour chlorine smell/taste, as my encounter was a small amount inhaled accidentally orally.