Okay- So I got a chemical order today from good ol' elemental... and I noticed something wierd about my NaF. It was blue... I can compare the
coloration to finely powdered copper sulphate.
I am at my wits end- I know that sodium fluoride is supposed to be white. However, it frightens me to use this in any experiment because what if that
is not what it is...?
Anyone think of any possible scenario? If it's not NaF, how do I know my other chemicals are what the say they are?!Hexavalent - 28-9-2012 at 11:25
Have you asked Elemental? Perhaps there was something wrong with that batch.
It could well be a copper halide salt as contamination (or any other copper salt actually), but take this with only a pinch of salt. I seem to
remember someone having a problem with some sodium thiosulfate from Elemental once, as it passed no lab tests for it and concluded it simply wasn't
the thiosulfate - this could be a similar thing.
[Edited on 28-9-2012 by Hexavalent]kristofvagyok - 28-9-2012 at 13:35
Anyone think of any possible scenario? If it's not NaF, how do I know my other chemicals are what the say they are?!
Long ago I have bought some table salt, some commercial NaCl to eat. It was blue! I haven't eated it, but I have checked the scientific literature
from this.
The blue colorination could be caused by 2 things, at first by the production method of the salt. Lithium-hydridie is also sometimes blue, because a
few ppm concentration of "metallic" lithium is left in the crystals and they have a blue color at low concentrations. Why? Because they react molten
lithium with hydrogen and the LiH crystals settle down to the bottom of the liquid Li....
But as far I know NaF would be extremely expensive if they would make it by this method.
The second thing what could result the blue colorination of NaCl/NaBr/NaF that high energy radiation e.g.: gamma rays damage the crystal structure and
at a few spots and sodium ions could get into majority what could also cause this colorination. The blue color in this case will fade in 5-8 years.
Recrystallize it from any solvent and it will fade. If not, then something is in it.ScienceHideout - 28-9-2012 at 15:11
Here is something a bit interesting:
I looked up NaF in my book- the Hawley's Condensed Chemical Dictionary.
I should've consulted this in the first place! It says that insecticide grade NaF is blue in order to stop people from eating it. It is purposely
died!bob800 - 28-9-2012 at 15:26
I've had a similar experience with some sodium sulfate from Elemental — it appeared to be mixed with some sort of fine, red sand. After a
recrystallization, however, I was left with what looked to be pure Na2SO4... but still, I don't see how a well-established supplier like Elemental
considers this acceptable.
