Sciencemadness Discussion Board - Halogen Colors

Halogen Colors

Drunkguy - 6-8-2009 at 09:31

This might sound weird since in molecular modeling oxygen is red, nitrogen is blue, and hydrogen is often gray.

However, I want to know what the color of fluorine is.

I have read in text books at high enough concentration it is a pale blue.

Whenever people do computational chemistry it is often made to look similar to chlorine (ie greenish).

Does anybody have good quality photos of fluorine at high enough concentration (liquified if possible)?

Drunkguy - 6-8-2009 at 09:34

This one looks almost like lime: http://library.thinkquest.org/C0113863/Fluorine.shtml

Interestling since definately I had been getting it confused with the color skyblue.

See my attachment. Is that accurate or not?

[Edited on 6-8-2009 by Drunkguy]

Ozonelabs - 6-8-2009 at 09:52

Most of the Fluorine that can be seen online is Pale yellow.

We can show you liquefied Chlorine if that's of interest?

UnintentionalChaos - 6-8-2009 at 10:23

http://periodictable.com/Items/009.5/index.html

woelen - 6-8-2009 at 11:08

The picture of Drunkguy seems to be fake to me. I believe it is chlorine gas, or maybe dilute chlorine dioxide. True fluorine apparently has a much weaker color. That picture posted by UnintentionalChaos seems very brown to me, but other people also told me that a true fluorine sample has a brownish appearance. Maybe it is yellowish/brown,. and the color rendering of the image posted by UnintentionalChaos is somewhat too brown?

EDIT: Fixed unfortunate offending typo

[Edited on 7-8-09 by woelen]

Drunkguy - 6-8-2009 at 11:38

Drunkgay? WTF

Ozone - 6-8-2009 at 18:31

I'm wondering if the pic from Drunkguy (ROTFLMAO--I am sure that was a typo!) might contain water (HF) and the color might be from the mix attacking the glass (otherwise, it looks like chlorine)? The pic from UC looks orange or red to me, not inconsistent, perhaps with something like dilute Br. Is this what perfectly dry pristine fluorine looks like under *deactivated* quartz?

Does the picture truly represent the model object?

Interesting,

O3

not_important - 6-8-2009 at 21:46

Quote:

When examined in a thickness of one meter, it is seen to possess a greenish yellow color, but paler, and containing more of yellow, than that of chlorine. In such a layer, fluorine does not present any absorption bands.

http://chestofbooks.com/crafts/scientific-american/sup7/Phys...

woelen - 6-8-2009 at 23:03

Quote: Originally posted by Drunkguy

Drunkgay? WTF

My apologies, it was not my intent to upset you. This was an unfortunate typo

Probably this is because last week we had the gay parade in Amsterdam and we were reading lots and lots about it.

JohnWW - 6-8-2009 at 23:20

As one goes from fluorine to astatine, the absorption band of the UV/visible spectra of the diatomic halogen molecules progressively increases in wavelength and thus decreases in energy, this being also a function of the energy required to dissociate the molecules. This is why fluorine is pale yellow (peak absorption being near the violet-UV boundary), chlorine is green, bromine is reddish-brown, and iodine is purple (peak absorption in the middle of the visible spectrum). The colors of the univalent inter-halogen compounds, such as ClF, BrF, ICl, etc., would be intermediate between those of the pure substances.

Has anyone ever seen a macroscopic quantity of astatine (At), at least in the vapor or liquid phase? - I would think it would probably be blue, due to peak absorption probably in the red, but of course the intense radioactivity (and toxicity if ingested, like polonium) of all its isotopes (longest-lived one has an half-life of only 8.3 hours) makes it hard to obtain (usually by bombarding Bi-209 with alpha particles) and view any macroscopic quantity; do not try it at home.

[Edited on 7-8-09 by JohnWW]

hodges - 7-8-2009 at 14:17

Quote: Originally posted by JohnWW

Has anyone ever seen a macroscopic quantity of astatine (At), at least in the vapor or liquid phase? - I would think it would probably be blue, with peak absorption probably in the red.

Per CRC, the most stable isotope has a half-life of about 8 hours. It is considered the rarest of the elements because of this. Since it has to be synthesized on demand through a nuclear reaction, probably few people in the world have seen macroscopic amounts.

Hodges

pantone159 - 7-8-2009 at 15:02

I have this picture of liquid F2. (Condensed with LN2).

woelen - 9-8-2009 at 11:25

Quote: Originally posted by hodges

Quote: Originally posted by JohnWW

Has anyone ever seen a macroscopic quantity of astatine (At), at least in the vapor or liquid phase? - I would think it would probably be blue, with peak absorption probably in the red.

Actually, very few people. I would say: nobody. A compound with a half-life of just 8 hours is so increadibly radioactive that no more than nanogram quantities can be handled. If it really would be possible to see vapor or crystals of this element, then there would be pictures of that. But as far as I know, there are no such pictures and I can understand why.

pantone159 - 9-8-2009 at 13:29

Quote: Originally posted by woelen

Quote: Originally posted by hodges

Quote: Originally posted by JohnWW

Has anyone ever seen a macroscopic quantity of astatine (At), at least in the vapor or liquid phase?

I have tried to scour the net for photos of At (and any other elements where I can't collect a macroscopic physical sample!) and have never found anything, I am not at all surprised for this reason.

OTOH - Does anybody know of any photos of Actinium? I think it has been seen, but I have never seen a picture of the element.

12AX7 - 9-8-2009 at 14:27

The strange thing about nuclear materials is, few people ever see them. They are handled remotely, behind thick shielding. Reports of Cs137 chloride (released in the Goana accident) seem surprised to tell of the volumetric blue glow, as though it had never been seen by western eyes before. Such a shame.

Others, like actinium, don't have much use, so aren't produced in quantity.

It really is a shame. Every element needs a picture!

Tim

Pyrovus - 9-8-2009 at 22:14

Any intrinsic colour of the astatine would be vastly drowned out by the light released as a result of the radioactive decay - Astatine 210 releases about 13000 kJ/mol/sec of energy through decay. As such, if a visible sample of astatine were prepared, I imagine it would look a lot like the surface of the sun.

not_important - 9-8-2009 at 23:21

Quote: Originally posted by pantone159

OTOH - Does anybody know of any photos of Actinium? I think it has been seen, but I have never seen a picture of the element.

http://www.rsc.org/chemsoc/visualelements/PAGES/data/actiniu...

12AX7 - 9-8-2009 at 23:32

I don't buy it. How big does that slug have to be? At least a few micrograms. Maybe as big as a grain of rice. Actinium is over a hundred times more radioactive than radium, and a single gram of radium produces a huge blue halo. Even with bright lighting, I don't think that slug would look so plain. Interesting that it's photographed on a blue background, though... that's just the thing to hide such a halo.

Tim

bfesser - 10-8-2009 at 07:26

That image looks computer generated.

pantone159 - 10-8-2009 at 12:56

Quote: Originally posted by not_important

http://www.rsc.org/chemsoc/visualelements/PAGES/data/actiniu...

Interesting. I want to be skeptical as are others, although all the images I found similar to this looked legit.

watson.fawkes - 10-8-2009 at 13:04

Quote: Originally posted by 12AX7

Even with bright lighting, I don't think that slug would look so plain. Interesting that it's photographed on a blue background, though... that's just the thing to hide such a halo.

It's entirely possible the photo was taken on a white background, in the dark, through a telescope. I'm sure the actual story of how much government money was spent getting the photo is, at least, droll.

Jdurg - 21-8-2009 at 20:21

I'd be willing to put my entire life savings on the line betting that the photo is NOT of Actinium. The only place that I know of which may have images of pure metallic Actinium would be the British Government. I believe they own virtually the entire world's supply of Actinium and have photographed it many times, but those photographs are not released to the public.

(I know, I've tried.

)

chloric1 - 22-8-2009 at 04:13

Quote: Originally posted by Pyrovus

Any intrinsic colour of the astatine would be vastly drowned out by the light released as a result of the radioactive decay - Astatine 210 releases about 13000 kJ/mol/sec of energy through decay. As such, if a visible sample of astatine were prepared, I imagine it would look a lot like the surface of the sun.

If that is the case, then I wish I could see a concentrated solution of fuming hydroastinic acid. It would be like fuming liquid sunshine. :cool:

not_important - 22-8-2009 at 06:58

Quote: Originally posted by Jdurg

I'd be willing to put my entire life savings on the line betting that the photo is NOT of Actinium. The only place that I know of which may have images of pure metallic Actinium would be the British Government. I believe they own virtually the entire world's supply of Actinium and have photographed it many times, but those photographs are not released to the public....

Well, the link I gave was to the site of the Royal Chemical Society, so you'll have to talk to them re the factual state of the image; it is conceivable they might have better contacts with the British government than you.

However the Brits are not the only ones with actnium, see here for example
http://www.inl.gov/featurestories/2006-03-02.shtml

Quote:

INL Researchers have developed two separations processes that recover actinium-225 from nuclear waste, increasing world production by 75X, doubling available source material, and enabling clinical cancer trials to proceed.

And there is this http://www.ornl.gov/sci/nuclear_science_technology/nu_med/pr...

And there is another image of actinium out there, which does have a blue halo.

Actinium.jpg - 19kB

unionised - 23-8-2009 at 05:20

Quote: Originally posted by bfesser

That image looks computer generated.

Are you, by any chance, looking at it on a computer?

pantone159 - 23-8-2009 at 07:08

Quote: Originally posted by Jdurg

The only place that I know of which may have images of pure metallic Actinium would be the British Government. I believe they own virtually the entire world's supply of Actinium and have photographed it many times, but those photographs are not released to the public.

Are you thinking of Protactinium instead? IIRC the British did separate a considerable amount of Pa many years ago, and made this available to other researchers. It is apparently a real hassle to separate it, it forms some polymeric goop when hydrolyzed, or something like that.

I don't have any pictures of Pa metal either, only some of Pa oxide.

As far as the last pic of Ac, I think that the blue glow is simulated. The first one seems to be too big a piece for me to really believe it is Ac. (However it is hard to tell the size.) I'd expect a piece of material that contains Ac along with mostly other things. (E.g. natural U metal, a used fuel rod (would that give you more Ac???), or something.)