Doktor Klawonn
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Microchemistry: White Phosphorus
Introduction
There are several experiments posted on white phosphorus here already.[1] Some of them use lethal amounts of the substance. It is however possible to
show the properties of white phosphorus using only a few milligrams of it.
Chemicals
- red phosphorus
- glas tubing
- burner
- Q-tip
Warning
In this experiment, white phosphorus is produced. White phosphorus is very poisonous and highly flammable. Do not repeat this experiment at home.
Experimental
A micro test tube is made from ordinary glas tubing.
5 mg of red phosphorus are placed into the prepared tube. The open end is closed with a Q-tip. The side with the red phosphorus is heated over a
flame.
![p2.JPG - 9kB](http://www.sciencemadness.org/talk/files.php?pid=194892&aid=12312)
The produced white phosphorus condenses into the Q-tip.
![p3.JPG - 12kB](http://www.sciencemadness.org/talk/files.php?pid=194892&aid=12314)
It immediately catches fire when drawn out into air.
![p4.JPG - 7kB](http://www.sciencemadness.org/talk/files.php?pid=194892&aid=12316)
Remaing white phosphorus in the tube glows in the dark. The glowing can be stopped by closing the tube or can be increased by injecting air into the
tube.[2]
Remarks
The red phosphorus depolymerises to white phosphorus upon heating. The produced white phosphorus condenses into the Q-tip in a finely divided form. It
catches fire immediately in contact with air.
Waste
The tube is heated while air is injected into it to remove any phosphorus. The Q-tip is burned.
Links
[1] See this thread
[2] The video camera didn't see the glowing.
[3] This experiment in a video
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madscientist
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Quote: | Do not repeat this experiment at home. |
That's exactly what everyone here will do.
I weep at the sight of flaming acetic anhydride.
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woelen
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This is the type of experiments I like. It does not look too dangerous, given the tiny amount of red P used. I see the handling of the glass tube and
the flame as a higher risk than the handling of this tiny amount of red (and later white) P.
Thanks for posting and I'll certainly try this at home
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kuro96inlaila
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Lol,
It seems that phrase "Don't try this at home" will make whoever more interested to try it!![;)](./images/smilies/wink.gif)
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kuro96inlaila
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Anyway,nice experiment!
And very interesting!
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hkparker
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Yea on saw the video on this because I subscribe to your channel ![:D](./images/smilies/biggrin.gif)
Anyone think this would be a practical way to produce white P from red P on a slightly larger scale?
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kuro96inlaila
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I think i've seen someone making white phosphorus by heating red P on this forum,
just forgot who post it and where it is.![:P](./images/smilies/tongue.gif)
Got to find it back~
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woelen
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I have done that:
http://woelen.homescience.net/science/chem/exps/RedP2WhiteP/...
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hkparker
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Oh awesome, thanks woelen!
My YouTube Channel
"Nothing is too wonderful to be true if it be consistent with the laws of nature." -Michael Faraday
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MagicJigPipe
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I have, in the past, scraped a fraction of a gram or so of "red P" from match strikers and placed them in a crucible. I held a flame to the
phosphorus for a short time then immediately took the crucible to a dark room. I saw that it was clearly glowing, an indication that white P was
made.
This seems to be nothing new, or am I missing something?
On a larger scale where yield is important, obviously something so hasty and simplistic won't work.
"There must be no barriers to freedom of inquiry ... There is no place for dogma in science. The scientist is free, and must be free to ask any
question, to doubt any assertion, to seek for any evidence, to correct any errors. ... We know that the only way to avoid error is to detect it and
that the only way to detect it is to be free to inquire. And we know that as long as men are free to ask what they must, free to say what they think,
free to think what they will, freedom can never be lost, and science can never regress." -J. Robert Oppenheimer
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