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Aemornion
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[*] posted on 12-9-2017 at 10:14
Osmium tetroxide decomposition


Hello all,
I have been gifted a rather impressive stash of chemicals.
(Still itemizing them I'll be selling some eventually)

One of the nastier ones happens to be osmium tetroxide.
I'll have to xray the one can to see what's inside, the other can has 3 vials each with an unknown quantity.
Thankfully its stored appropriately. Looks to be in good shape, nothing degrading or black.
I added a few more layers and another can just to be safe.

Needless to say, I don't really want the tetroxide hanging around. That is pushing the limits on what I'm willing to store for an extended period of time.

Corn oil is the recomended way to neutralize the tetroxide, for Those who don't know.
But I also don't want to get rid of the osmium metal.

Anyone have a good way to reduce it back to the metal.
I'd love to put the metal in an ampoule under argon.

I have access to a glovebox/hood, safety is no stranger to me.
Just looking for some suggestions on the process, not a lecture on safety.

Note: if someone wants it.. I'm more than happy to trade it for an equivilant quantity of osmium metal.
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Melgar
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[*] posted on 12-9-2017 at 11:02


Corn oil will reduce the tetroxide to the metal, and you'll then be able to see it as a black powder that will settle out. Wash it with something really neutral like hexane.



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[*] posted on 12-9-2017 at 14:38


Reducing osmium should be possible with hydrogen

OsO4 is very soluble in tert-butyl alcohol. In solution, it is readily reduced by hydrogen to osmium metal. The suspended osmium metal can be used to catalyze hydrogenation of a wide variety of organic chemicals containing double or triple bonds.

OsO4 + 4 H2 → Os + 4 H2O





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[*] posted on 12-9-2017 at 14:42


You should have no problem selling Os powder once you have cleaned it.
Actually, you probably won't have any difficulty selling OsO4 in the containers it is currently in. Shipping it legally might be another matter, however.
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AJKOER
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[*] posted on 12-9-2017 at 15:28


OK, not a safety lecture, more like a sanity test, to quote from Atomistry.com on OsO4:

"The tetroxide readily sublimes on heating. When fused it boils at 100° C., yielding a vapour of density 8.89 (air = 1) or 128 (H = 1), the theoretical requirement for the formula OsO4 being 127.5 (H = 1). The vapour is very penetrating and exceedingly poisonous, producing temporary blindness and other alarming symptoms. If inhaled, the best antidote appears to be hydrogen sulphide, which neutralises the action of the tetroxide on the respiratory organs."

Sounds like a pretty scary compound, I would not keep it around. Now with respect to the metal, to quote again:

"Finely divided metallic osmium slowly oxidises in air to the tetroxide, and more rapidly on heating in air or, better, in oxygen. At high temperatures the compact metal yields vapours of the volatile tetroxide, and this affords a useful means of quantitatively separating osmium from its iridium alloy."

So, the metal itself appears to be a rapid avenue back to OsO4.

Source link: http://osmium.atomistry.com/osmium_tetroxide.html

[Edited on 12-9-2017 by AJKOER]
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Aemornion
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[*] posted on 12-9-2017 at 17:52


Melgar,
I was under the impression that the corn oil generated Os, OsO2 and, OsO. All less problematic than OsO4 of course.
Are you certain that only Os is precipitated?

Symboom,
As far as the hydrogen reduction goes, as far as apparatus goes, would one simply pass finely bubbled hydrogen through a column of the tert-butanol?

ALJKOER,
You are correct, especially if it's powered.
Which is why I plan to be working in a fume hood, and then an argon inert glove box. I don't enjoy taking risks.
End game would be to seal the powder in an ampoule under argon. I doubt I'll ever be able to solidify it.

Yea, the house the chem stash came from is crazy.,
The gentleman who passed away had HF in his kitchen along with a large quantity of mercury.,
And the OsO4 was supposedly in box under a bunch of other heavy stuff in his living room.
Think the horders tv show... But with piles of science... Everywhere...
Crazy...

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[*] posted on 12-9-2017 at 18:08


Quote: Originally posted by Aemornion  

Think the horders tv show... But with piles of science... Everywhere...

Score!!
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[*] posted on 12-9-2017 at 22:40


The dangers of OsO4 are somewhat exaggerated over here. The way it is stored, it is quite safe, just assuree that the container(s) cannot break, but wrapping in paper tissue and keeping a second bigger container around it.
I assume you just have a few grams and then the whole storage issue nearly is non-existent, when the above is taken into account.

Another way to keep it around safely is to break the well-cleaned ampoules under water with a clean glass rod or stainless stell rod. Once the ampoule is broken, you can dissolve the OsO4 and obtain a solution of a few tenths of percents concentration, which can be used for interesting experiments. Such a solution is stable and does not give off any OsO4 vapour. It can be stored in a glass bottle with a plastic screw cap.

The vapor indeed is dangerous, but when you do as described above, there is no risk of getting a large amount of vapor in your house.

I would not destroy it. You even could sell it to someone and get a nice amount of money for it. It is worth at least a few tens of dollars per gram.




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Melgar
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[*] posted on 13-9-2017 at 02:45


Quote: Originally posted by Aemornion  
Melgar,
I was under the impression that the corn oil generated Os, OsO2 and, OsO. All less problematic than OsO4 of course.
Are you certain that only Os is precipitated?

I thought that OsO2 and OsO were strong enough oxidizers to be reduced by corn oil, but I guess I'm not 100% sure.




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[*] posted on 13-9-2017 at 03:09


Like I said,
If someone here wanted it, id be more than happy to trade it away...
I think if I were to simply list it on eBay it would be taken down, due to the potential of someone using it for ill-intent.
Not to mention I'm unsure how many hoops one would have to jump through to ship it. Probably just specify pickup only.
Trading it would be better, someone gets to use the material rather than me destroying it, and I get the slightly more mundane osmium metal.

Their are at least 3 1g vials in the one container.
The only reason I know what's inside it is because the can is not a positive closure can. just two half's what slide together. When I first picked it up the top slid off and I observed its contents, it has since been secured shut.
The 2nd container is a sealed paint can, slowly rocking it leads me to believe another quantity of 2 or more 1g vials. I'll know more once I X-ray it. (my buddy has a machine). I don't believe any vials to be broken.

You have to look at it from my perspective, I have a 1 year old.
True my chemicals are locked away in a cabinet, within the garage and the odds of exposure are low. But is the risk really worth it, to have one hanging around that such a small amount can become an extremely harmful vapor. Not Particularly.

It will be a while before I can make it up to the lab, so plenty of time for someone to decide if they want it or not.
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[*] posted on 15-9-2017 at 07:01


My advice is look up the book value of it in Alfa or through a supplier, and then donate it to your local university and write it off on your taxes. You will maximize value in that fashion by saving the university money on buying/shipping it and assure it goes to a good, responsible home.

Outside of someone doing certain organic syntheses, it's basically used for biological sample prep. That's what 95% of it is sold for in this day.

Otherwise, I can pay the shipping on it and a modest sum and take it off your hands--I don't have much real need for it, but do have to make it before I make ammonium chloroosmate into Os sponge. All refined osmium goes through the distillation process, which is remarkably simple and effective, but of course dangerous without the proper setup.

As for the Os powder thing...VERY fine powders stink. Well sintered powder (calcined in Ar/H2 for about 10 h at 1000 C) gives off no odor and is just nice blue sand. Beautiful metal.




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[*] posted on 17-9-2017 at 11:44


Are there any Os compounds which do not spontaneously oxidize to tetroxide?
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[*] posted on 18-9-2017 at 07:04


How stable in air are perosmates? Osmates?
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[*] posted on 7-11-2017 at 09:30


Quote: Originally posted by AJKOER  
OK, not a safety lecture, more like a sanity test, to quote from Atomistry.com on OsO4:

"The tetroxide readily sublimes on heating. When fused it boils at 100° C., yielding a vapour of density 8.89 (air = 1) or 128 (H = 1), the theoretical requirement for the formula OsO4 being 127.5 (H = 1). The vapour is very penetrating and exceedingly poisonous, producing temporary blindness and other alarming symptoms. If inhaled, the best antidote appears to be hydrogen sulphide, which neutralises the action of the tetroxide on the respiratory organs."

Sounds like a pretty scary compound, I would not keep it around. Now with respect to the metal, to quote again:

"Finely divided metallic osmium slowly oxidises in air to the tetroxide, and more rapidly on heating in air or, better, in oxygen. At high temperatures the compact metal yields vapours of the volatile tetroxide, and this affords a useful means of quantitatively separating osmium from its iridium alloy."

So, the metal itself appears to be a rapid avenue back to OsO4.

Source link: http://osmium.atomistry.com/osmium_tetroxide.html

[Edited on 12-9-2017 by AJKOER]



Unbelievable.
The antidote for something quite deadly, turns out to be something which is also quite deadly. Who'da thunk.




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[*] posted on 16-11-2017 at 03:54


I have an ancient osmium tetroxide sample of 1g in my exotic stuff section:

WP_20171116_002.jpg - 108kB

Evil substance....I remember that I knew nothing of the dangers when I acquired this ampule.




Exact science is a figment of imagination.......
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