Sciencemadness Discussion Board

No F2 in element webshops : why ?

metalresearcher - 31-5-2011 at 01:21

On several webshops like www.elementsales.com or www.smart-elements.com samples of evenry element till 83 (Bi) are available, except Tc and Pm which are too radioactive. Obvious. But wat also lacks is Fluorine. Yes I know it is too reactive to put it into a sealed glass ampoule, it would attack the glass. The same with PMMA or Lexan.

But why not in transparent Teflon ? That is inert to F2 gas.


[Edited on 2011-5-31 by metalresearcher]

hissingnoise - 31-5-2011 at 01:51

Translucent teflon, yes, but I don't think it gets anywhere near as transparent as glass!
And I'd be surprised if there's any material that will contain it indefinitely . . .


woelen - 31-5-2011 at 02:07

Some years ago smart-elements sold a sample of F2 in a quartz ampoule. One part of F2 was mixed with 2 parts of an inert gas and this mix was sealed in the quartz tube. The gas mix had a very faint yellowish/brown color. This sample was outrageously expensive (EUR 300) and I wonder how long such a sample will last.

hissingnoise - 31-5-2011 at 02:21

Wiki says this about containment . . .

The WiZard is In - 31-5-2011 at 07:01

Quote: Originally posted by metalresearcher  
On several webshops like www.elementsales.com or www.smart-elements.com samples of evenry element till 83 (Bi) are available, except Tc and Pm which are too radioactive. Obvious. But wat also lacks is Fluorine. Yes I know it is too reactive to put it into a sealed glass ampoule, it would attack the glass. The same with PMMA or Lexan.

But why not in transparent Teflon ? That is inert to F2 gas.

Fluorine's cousin.

7. The permeability of glass to iodine and bromine vapours.
James Brierley Firth. Jour. Chem. Soc. Lond., 117, 1602-3 (1920).

—Iodine and bromine do not diffuse through glass under ordinary
experimental conditions. Only in extreme cases is there a
possibility of such diffusion. After a period of nine and one-half
years, iodine was found to have passed through a glass bulb 0.208
mm. thick. The bulb was heated to 360 °C for 100 days during the
experiment. In this experiment the bulb was placed in a large tube
and both tube and bulb evacuated. In another case, in which
iodine was found to pass through 0.211 mm. of glass, there was a
vacuum outside of the bulb and atmospheric pressure inside. here
was no evidence of bromine passing through a similar thickness of
glass after nine and one-half years. J. L. C.

http://tinyurl.com/33ct5wb

I wonder if there is still time to sign up?!

https://www.dnsc.dla.mil/pdf/Iodine%20BOA_Final.pdf

http://www.iodinenetwork.net/Resources_Iodine_Industry.html

Byda the US National Stock Piles biggest problem is Tin Disease
once it starts the only cure it to sell the infected tin off before the
disease spreads.

neptunium - 18-12-2012 at 16:33

did you see that video?

https://www.youtube.com/watch?v=vtWp45Eewtw

pretty cool huh!

need we say more about F2 reactivity?

[Edited on 19-12-2012 by neptunium]

Pyro - 18-12-2012 at 16:48

if you want to see it, make it!
have you guys heard of the idea about keeping F2 in a CaF2 container? it's supposed to work.

kristofvagyok - 18-12-2012 at 16:57

There IS F2 in webshops, the only thing what is important when buying a sample is the believing that your sample contains some of it.

https://www.youtube.com/watch?v=TQDjILTly3s

Mineral webshops offers large, nice samples of fluorite, buy some and hope that it contains a few atoms of elemental fluorine(:

bahamuth - 18-12-2012 at 17:21

This guy has a tube quartz tube with the stuff and the recipe to make one your self:
Real visible fluorine. (http://periodictable.com)

neptunium - 18-12-2012 at 17:24

pretty cool! Theo has some very nice samples!


[Edited on 19-12-2012 by neptunium]

99chemicals - 18-12-2012 at 18:15

Could you theoretically use a CaF2 vial to store Florine or would it react? If you grew a crystal and milled a lid and bottle body with a CNC? Obviously that would be very expensive.

UnintentionalChaos - 18-12-2012 at 18:53

Quote: Originally posted by 99chemicals  
Could you theoretically use a CaF2 vial to store Florine or would it react? If you grew a crystal and milled a lid and bottle body with a CNC? Obviously that would be very expensive.


Large blocks of perfectly clear CaF2 are already used to produce optical components. I'm sure that a vessel could be made and polished to glass-like transparency, filled with completely anhydrous F2 through a tiny hole, and sealed, perhaps with a polished, very high surface area taper and an extremely fine film of perfluorinated grease.

Heavy metal fluoride glasses may also be an option for a more conventional ampoule, but would need a secondary ampoule to protect it from atmospheric moisture.

woelen - 19-12-2012 at 00:04

O yes, I think that it is possible to make a sample of fluorine, contained in some glass-like metal fluoride, but the cost of making such a thing, just for display purposes, would be enormous. Probably a decent size sample will cost thousands of dollars and nobody is willing to pay such an amount for such a sample, especially if there is uncertainty about how long such a sample will last.

I remember having seen pictures of samples of fluorine in ordinary glass ampoules, containing a clearly visible brownish/green gas mix, but I think that these were fake. This ampoule has been on the Wiki page for fluorine for a while, but the picture was removed very quickly. Of course you can make fake ampoules containing a little NO2 and mostly Cl2 (which, if made dry do not react with each other) and most people won't notice, because nearly no one really knows how fluorine looks like. Especially if the gas mix is not too concentrated and the color is only weak (which apparently is the case with real fluorine), then I think that most people won't notice the fake content.

paulr1234 - 19-12-2012 at 01:18

With some persistence, earlier this year, I finally got a response from the guy that Bahamuth links to. He was willing to make one of those Si-encapped, teflon grease treated tubes for me but he wanted a lot (a thousand bucks or so if I remember correctly.)

You can have a pretty decent night in Vegas with a $1,000.

Endimion17 - 19-12-2012 at 03:23

A thousand dollars? Is he insane?
I've seen that link long time ago and I agree it's possible. But a thousand dollars? LOL

Fluorine is very, very pale in colour, therefore a decent tube is needed.

Lambda-Eyde - 19-12-2012 at 05:06

There was a discussion on /r/chemistry about this a few days ago: http://www.reddit.com/r/chemistry/comments/148zbn/i_want_thi...

neptunium - 19-12-2012 at 06:11

making F2 and its container is hardly a weekend home chemist endavour! it take platinum electrodes and CaF2 mix with HF to electrolysis... i mess with clorine and bromine but Fluorine is a whole different ball game ... besides fluorides are toxic and so is F2, it could be done but what a mess it would be to clean afterward! and how much would it cost in equipment just for that one experiment ...

Dr.Bob - 19-12-2012 at 06:37

For $1000 you could likely buy an entire cylinder of F2. It would certainly not be transparent, but you could create a giant mess with it if it leaks. But it would be a real sample.

I used to work (long ago) at a company with F2, HF, and several other lovely gases, and the EPA/OSHA/ETC would require yet more containment and more special ventilation every few years, until it became impossible to work with. Now the same work is likely done in China by people with little training, no safety equipment, and little clue what they are doing.

neptunium - 19-12-2012 at 07:18

and even with the money i doubt anybody would sale to a home chemist.....they wont even sale chlorine !

Transparent medium to store elemental F2 ?

metalresearcher - 11-8-2013 at 22:32

The site www.smart-elements.com supplies all nonradioactive elements except Fluorine.
This sample is actually a sample of CaF2 and not elemental F2. There is no transparent medium such as glass, quartz, Al2O3, etc. which can hold F2 without being attacked. But I know that teflon does withstand F2 and that transparent teflon exists as well. So why these acryl boxes not coated with transparent teflon on the inside ?



[Edited on 2013-8-12 by metalresearcher]

papaya - 11-8-2013 at 23:25

Yes, it's CaF2 :D

bahamuth - 12-8-2013 at 00:13

I guess since Teflon is as gas tight as a sieve and would not hold it for prolonged periodes.



Searching the forum gives:


No F2 in element webshops : why ?

Edit:
And quartz can hold fluorine, as can be read and seen in the aforementioned thread.

[Edited on 12-8-2013 by bahamuth]