Fyndium
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Vapor pressure of toxic solids?
Is there any risk that a solid could emit enough vapors to cause health risk? I thought this when handling lead acetate and after considering
everything else I thought could I still be breathing it? Hydrates, especially in form of crystals do not appear to cause airborne dust particles,
unlike some anhydrous powders which just float everywhere.
The vapor pressure of said substance is 0.1Pa.
[Edited on 10-10-2020 by Fyndium]
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MidLifeChemist
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Sure. Osmium tetroxide is considered dangerous for this reason.
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Fyndium
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The compound seems to have quite low boiling point of 126C, hence no wonder. Its VP is 7mmHG which translates to 1kPa, 10 thousand times higher than
my reference.
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unionised
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Which is about a millionth of an atmosphere.
Plenty of materials are toxic enough that breathing air containing 1ppm of them would be a bad idea.
Obviously, it's unlikely that you would actually reach the equilibrium concentration but...
Warm, but solid, naphthalene can generate enough vapour to exceed the TLV.
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Herr Haber
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Osmium tetroxide... vapor ? You probably thought dust right ?
The spirit of adventure was upon me. Having nitric acid and copper, I had only to learn what the words 'act upon' meant. - Ira Remsen
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MidLifeChemist
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No, I thought vapor. The poster did not ask about dust.
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Fyndium
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Dust can be more easily controlled with good working practices and with simple breathing filters, but vapors need more.
What I was after here that how realistic or acute is the exposure to said low vapor pressure substances, if we are speaking minute exposures, no
occupational? Is it possible to estimate the actual amount of material absorbed in the body? For lead, daily average intake is 100ug and tolerable
limit for people is 250ug in their normal diet and life.
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teodor
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Quote: Originally posted by Fyndium  | Dust can be more easily controlled with good working practices and with simple breathing filters, but vapors need more.
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I think the opposite. Many vapours could be vented out or neutralised but dust is a subject for more precise treatment.
But let specify which solids we are talking about. There are different nuances with each of them.
[Edited on 12-10-2020 by teodor]
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Fyndium
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This hazard came up because I were just recently handling lead oxide and lead acetate.
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teodor
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Micro quantities of lead will not make any harm, as you know people in past used its compounds everywhere. Only accumulation is the thing which
matters, also it has direct danger to small and not born yet children.
So, if accumulation is the thing which matters then the dust, cleaning procedures & waste processing become most important.
As for vapours, I doubt PbO has any appreciable amount and PbAc2 has probably the same level as Pb(NO3)2 which is considered quite low at room
temperature.
My most concern when working with lead compounds is my sleeves. I think they can accumulate a lot of micro droplets when I do washing etc. so my next
safety measurement will be probably a lab coat.
As for wast processing I used a bottle but decided to buy a bigger plastic drum. I put NaOH solution inside and Na2Sx which converts all lead into PbS
which is precipitated on the bottom on prolonged standing. I would not reccomend to use Na2CO3 because it cause effervescence (so many air-flying
micro droplets) with acidic solutions. Also concentrated NaOH dissolves filter papers.
Na2Sx causes H2S smell so I will try replace this system with NaOH & Na(OCl)2 which causes precipitation of PbO2.
So, generally, I would more bother with splashing of solutions, washing procedures and dust accumulation in your lab and you should be alive if don't
eat Pb salts on everyday basis.
But. If you process lead from e.g. batteries, it can contain other dangerous compounds with different properties as well.
0-2020 by teodor]
[Edited on 12-10-2020 by teodor]
BUT of course we were talking about lead (II) acetate because lead (IV) acetate is quite different thing and has a different level of danger.
[Edited on 12-10-2020 by teodor]
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Herr Haber
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Well, I guess I'd have found out sooner or later since I have Osmium in my shopping list for the element collection but thank you for the heads up !
Sooner is always better 
Darned interesting melting and boiling point though.
The spirit of adventure was upon me. Having nitric acid and copper, I had only to learn what the words 'act upon' meant. - Ira Remsen
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