Sciencemadness Discussion Board

Microchemistry: White Phosphorus

Doktor Klawonn - 12-12-2010 at 10:46


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.


- red phosphorus
- glas tubing
- burner
- Q-tip


In this experiment, white phosphorus is produced. White phosphorus is very poisonous and highly flammable. Do not repeat this experiment at home.


A micro test tube is made from ordinary glas tubing.

p6.JPG - 9kB

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

The produced white phosphorus condenses into the Q-tip.

p3.JPG - 12kB

It immediately catches fire when drawn out into air.

p4.JPG - 7kB

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]


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.


The tube is heated while air is injected into it to remove any phosphorus. The Q-tip is burned.


[1] See this thread
[2] The video camera didn't see the glowing.
[3] This experiment in a video

madscientist - 12-12-2010 at 10:54

Do not repeat this experiment at home.

That's exactly what everyone here will do. :P

woelen - 12-12-2010 at 13:09

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 :D

kuro96inlaila - 23-12-2010 at 16:45


It seems that phrase "Don't try this at home" will make whoever more interested to try it!;):P

kuro96inlaila - 23-12-2010 at 16:46

Anyway,nice experiment!
And very interesting!:D

hkparker - 23-12-2010 at 17:40

Yea on saw the video on this because I subscribe to your channel :D

Anyone think this would be a practical way to produce white P from red P on a slightly larger scale?

kuro96inlaila - 24-12-2010 at 06:27

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

Got to find it back~:(

woelen - 24-12-2010 at 07:23

I have done that:

hkparker - 24-12-2010 at 11:18

Oh awesome, thanks woelen!

MagicJigPipe - 26-12-2010 at 00:05

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.