a_bab - 13-2-2010 at 04:59
Few days ago, late at night I read from Mellor (thanks Sauron) and this morning I woke up with the impression I had (yet) another erotic chem dream.
Sodium phosphorescence!
Sure enough, falling asleep with the nose in a book may make you think in the morning that you reinvented the wheel or smth.
According to E. Linnemann the oxidation of sodium at ordinary temp. is accompanied by a greenish phosphorescence; and if, when the phosphorescence
has ceased, the metal he heated to 60-70 degrees C, the phosphorescence reappears. An analogous phenomenon occurs when sodium acts on water in
darkness. The bluish-white streak which sodium makes on paper shows a green phosphorescence which persists longer than the greyis-white streak made
by potasium because sodium is not so rapidly oxidized as potassium. (Mellor - chapter XX Alkali metals)
Any takers?
[Edited on 13-2-2010 by a_bab]
woelen - 13-2-2010 at 13:30
Off course, when I read this, I immediately tried. No phosphorescence at all, not even in complete darkness after the eyes become used to the
darkness. I also tried with a small piece of white P (I have some, which I made myself from red P) and the latter gives a clearly visible ghost-like
appearance of light around the solid piece. I did this comparison just to be sure that my eyes really are used to the darkness.
ScienceSquirrel - 13-2-2010 at 14:05
I would not discard it out of hand.
Some phenomena are fugitive.
I would try making metallic streaks on various grades and types of paper with sodium metal.
a_bab - 13-2-2010 at 15:45
The cited source is from 1850 or something, which may not be reliable. After all we have nowadays zillions of crap patents, and (I'm sure) not
verified statements in scientifical works - aka bullshit in papers, with no real research done, just to "be there".
I'll try myself as soon as I can this interesting phenomena.
garage chemist - 13-2-2010 at 23:35
My chemistry book (Hollemann-Wiberg) also claims that sodium and potassium give a chemoluminescence when freshly cut in complete darkness. It is only
visible on a fresh cut surface, and only lasts a few seconds. So one must cut the sodium in darkness to see it, in contrast to P4 which glows for
hours in air.
woelen - 14-2-2010 at 07:11
I indeed first cut the sodium and then I switched off the light. Cutting sodium in complete darkness is not really a safe thing to do.
Skyjumper - 6-3-2010 at 16:01
I tried cutting sodium under no light, and found no signs of phosphorescence (I'm surprised)
hissingnoise - 7-3-2010 at 11:02
If one had the patience to sit in an almost dark room for an extended period - long enough to become well accustomed to the semi-darkness and then cut
the sodium, one might be rewarded by a faint glow. . .