phosphorus odor?

[hermanntrude]

I have been planning an experiment using some red phosphorus, and today decided to have a closer look at my extremely old sample. It's in a can like a paint can, which worries me because the MSDS states it can ignite due to friction, and the can stays shut simply by friction and every time I open it i have to pry it open.

 

Not only that, but it stinks like sulfur. Why would it do that?

[dr.syntax]

I have been planning an experiment using some red phosphorus, and today decided to have a closer look at my extremely old sample. It's in a can like a paint can, which worries me because the MSDS states it can ignite due to friction, and the can stays shut simply by friction and every time I open it i have to pry it open.

 

Not only that, but it stinks like sulfur. Why would it do that?

 

REPLY: I don`t know why are you messing around with some old can of phosphorous . The horror stories of that stuff getting on people and burning in such a way that the only way to put it out was to cut away the burnig flesh. Phosphorous is dangerous stuff . I know there are different molecular forms of it but don`t think any of them are safe. I`d at least read up on it. Sounds dangerous to me. why would you want to take such risks just to do some experiment. I just googled it and found this website : http://mysite.du.edu/~jcalvert/phys/phosphor.htm . This website discusses phosphorous in detail. One of the comments made there was:" those who sniffed its vapors said it had a garlicky odor, before they died ". Take Care, ...Dr.Syntax

Edited September 29, 2009 by dr.syntax

[hermanntrude]

thanks for the advice, dr syntax, but i'm not inexperienced. The stuff I have is red phosphorus, perhaps contaminated with another allotrope. I've looked at the MSDS sheets (generally better than anecdotal scare stories) and they tell me that i'm safe if i dont inhale more than 50-100mg of pure white phosphorus. Also the garlic reference is to the smell of people's breath when they have inhaled or otherwise consumed too much white phosphorus... apparently it's one of the many symptoms of poisoning, along with vomiting, nausea and abdominal pain. Red phosphorus, btw is considered non-toxic by inhalation.

 

what concerns me is that perhaps my red phosphorus contains some white phosphorus, since it smells so bad.. or perhaps red phosphorus has a smell?

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certain MSDS sheets seem to be indicating that it's the combustion of P4 which results in the garlicky odor... perhaps it's the smell of the combustion products, P2O5 and others?

[John Cuthber]

Reaction with a metal tin and a trace of water might produce PH3 but I'm only guessing.

[dr.syntax]

thanks for the advice, dr syntax, but i'm not inexperienced. The stuff I have is red phosphorus, perhaps contaminated with another allotrope. I've looked at the MSDS sheets (generally better than anecdotal scare stories) and they tell me that i'm safe if i dont inhale more than 50-100mg of pure white phosphorus. Also the garlic reference is to the smell of people's breath when they have inhaled or otherwise consumed too much white phosphorus... apparently it's one of the many symptoms of poisoning, along with vomiting, nausea and abdominal pain. Red phosphorus, btw is considered non-toxic by inhalation.

 

what concerns me is that perhaps my red phosphorus contains some white phosphorus, since it smells so bad.. or perhaps red phosphorus has a smell?

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Merged post follows:

Consecutive posts merged

certain MSDS sheets seem to be indicating that it's the combustion of P4 which results in the garlicky odor... perhaps it's the smell of the combustion products, P2O5 and others?

REPLY: red phosphorous is considered safe as long as it is red phosphorous. Did you look at that website ? It was a very extensive discusion of phophorous . I may go back and reread it. I thought there was some discussion of red phosphorous transforming to white phosphorous under the right conditions. You did say it was an old can and descibed the warning. I have no doubt whatsoever that your knowledge of chemistry is far,far superior to mine. I had just remembered that it could be very dangerous. Please do be careful. My father was a chemist and I tend to think highly of them. ...Dr.Syntax

[hermanntrude]

The sample's original purity was only 90%, so I will have to assume that the impurity is white phosphorus and perhaps other allotropes and also that there might be some phosphine present. I will proceed on that basis. thanks

[jdurg]

Unless your phosphorus was stored under water, any white phosphorus in there would have rapidly burned up in the atmospheric oxygen. The faint garlic odor is characteristic of some phosphine gas as John Cuthber pointed out, but like so many odiferous gases, the nose picks up on the odor in INCREDIBLY minimal quantities. The percentage of white phosphorus that naturally formed in your can of red phosphorus is incredibly minimal. Nowhere close to 10%.

[hermanntrude]

so what could make up my 10% impurities then? other allotropes? black or violet perhaps?

[jdurg]

Substances which aren't phosphorus. Silicon, carbon, etc. etc. White Phosphorus is just not stable enough when exposed to the atmosphere to exist at all in the situation you describe. There may be a lot of other contaminants in the P that you have. (God that sounds horribly icky when I read it back out loud. ) I don't really have a good enough knowledge in how Red Phosphorus is produced on an industrial scale to know what else may be in there.

[Mr Skeptic]

I don't think that white phosphorous would necessarily ignite on contact with air. Does your sample glow greenish in the dark when exposed to air? In any case, if you leave it in the sun for a while that should get rid of any white phosphorous.

[hermanntrude]

white phosphorus DOES ignite in air if it's pure enough. The reaction is exothermic even if there are no flames. this heats up the sample until eventually it goes crazy, spraying molten phosphorus everywhere. Now I don't expect there's enough WP in my RP to make that happen, but I'm surely not going to go leaving it in the sun to find out. Not at a public college.

[jdurg]

I found this interesting little .pdf file with a google search regarding White P contamination in Red P; chemical_behaviour_of_red_phosphorus_in_water.pdf

 

To pretty much remove all White P in the Red P, you can go and wash your Red P with Carbon Disulfide, or some other organic solvent as White P is highly soluble in organic solvents while Red P is pretty much insoluble.