UnintentionalChaos
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"Smell" of oxidizers
I'm quite familiar with the awful smell of chlorine gas and the burning and stinging that accompanies it. Tonight, I was grinding some KMnO4 and it
became finely powdered enough that a bit of powder got airborne. Needless to say, I accidentally inhaled a bit (I immediately put a dust mask on
afterwards) and noticed that there was a nasty burning sensation and a particular momentary smell which reminded me immediately of chlorine. I was
wondering if the smell of chlorine is a direct result of the chlorine or of something being oxidized (akin in process to the "smell" of metal...If you
feel like smelling this, spill a bit of ferrous sulfate solution on your skin and take a whif...). I have never worked with bromine and was wondering
how close the smell is to chlorine. If bromine smells a lot like chlorine, the smell of an oxidation product could explain this similarity in the same
way that different metals can make very similar metallic smells. Then again, this is all speculation. Any thoughts?
Department of Redundancy Department - Now with paperwork!
'In organic synthesis, we call decomposition products "crap", however this is not a IUPAC approved nomenclature.' -Nicodem
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Furch
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I've read somewhere that what you smell when you smell chlorine is the same smell as with bromine, but also that of NOx. And the answer to why they
smell the same is because they oxidize the tissue with which you sense odours/smells.
Sounds reasonable to me... After all, NOx smell exactly the same as chlorine and bromine, and iodine too. And if you report that the permanganate ion
smells the same... That pretty much sums it up 
- Furch
\"Those who say do not know, those who know do not say.\" -Lao Tzu
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chloric1
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All these oxidizers have different electronic potentials. I notice the general smell of these potent oxidizers is very simular but NOT exactly the
same. NOx & Nitric acid resembles chlorine but it is sweeter and not quite as sharp. Iodine indeed is very pungent chlorine smell but somehow it
is "heavy" and sweet. It is difficult for me to put iodine into words. Bromine,aptly called stench, is every bit as sharp as chlorine and has a note
of a "bleach" smell. Chlorine dioxide, an even more powerful oxidizer, has an odor simular to a mix of chlorine and nitric acid. These smells are
all very simular but equally diSTINKtive just the same.
[Edited on 10/2/2007 by chloric1]
[Edited on 10/2/2007 by chloric1]
Fellow molecular manipulator
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UnintentionalChaos
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I should have posted this in general chemistry, and thought I had...but apparently not. I guess I was in the wrong forum when I hit new thread...
At any rate, thanks for the prompt responses. I know that they are not quite the same smell...Iodine is definetly different than chlorine...the
"smell" of permanganate was too brief to really comment on and I don't plan on repeating it.
I wonder if anyone has cared enough to find the compounds responsible as in the case of metal smells...probably not...
Department of Redundancy Department - Now with paperwork!
'In organic synthesis, we call decomposition products "crap", however this is not a IUPAC approved nomenclature.' -Nicodem
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MadHatter
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Nitrates
I won't speculate on oxidizers in general, but nitrates have a unique smell and taste, at least
to my senses. I won't taste salts of lead, barium, or any other number of toxic compounds,
but lead nitrate has that characteristic "sweet" odor of other nitrates. I must freely admit, that's
one group of chemicals whose smell I like ! 
From opening of NCIS New Orleans - It goes a BOOM ! BOOM ! BOOM ! MUHAHAHAHAHAHAHA !
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UnintentionalChaos
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I noticed that heated nitrates (like drying a kilo of NaNO3 crystals in a 180C oven...don't look at me like that...thats the smallest container I
could get ) give off a sickly sweet aroma. What is that smell from? Lead nitrate
(and acetate) is supposed to be sweet. It is something I'd taste once (not swallow), spit after, rinse with water, and wash my mouth with a sulfate a
few times, but its still recrystallizing right now.
Department of Redundancy Department - Now with paperwork!
'In organic synthesis, we call decomposition products "crap", however this is not a IUPAC approved nomenclature.' -Nicodem
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YT2095
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| Quote: | Originally posted by UnintentionalChaos
I noticed that heated nitrates (like drying a kilo of NaNO3 crystals in a 180C oven...don't look at me like that...thats the smallest container I
could get ) give off a sickly sweet aroma. What is that smell from?
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more than likely little pockets of trapped unreacted Nitric acid in the crystals, some damp indicator paper would have likely turned Red had that have
been in there too.
iirc, 180c is not hot enough to decompose it to the Nitrite.
as for KMnO4 smell, I get nothing like a halogen type smell from it, more of a very "Dry" type of smell is that makes sense.
\"In a world full of wonders mankind has managed to invent boredom\" - Death
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woelen
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For me, Cl2 and Br2 have very distinct smells, especially if they are not too concentrated. At higher concentration, when their smell becomes
burning/pungent, then their smells seem to converge.
NO2 again has a very different smell. It also is less pungent at similar concentrations (making it more dangerous, because its warning effect is
weaker).
I2 also has a different smell to me. It is sweeter, less pungent, than Br2 and Cl2. But at higher concentration, of course it becomes pungent as well.
I also once smelled gaseous CrO2Cl2 (accidently, at very low concentration) and that compound has a remarkable spicey smell. It has the smell of
plants, not unpleasant actually. At higher concentration, most likely its smell will be pungent, but I will not try that. Hexavalent chromium is a
carcinogen.
I never smelled KMnO4, and I think I want to keep it that way
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12AX7
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My NaClO3 inevitably has a slight fishy/musty odor. I don't know if it's necessarily an amine, or at least a simple alkylamine. I would have to
guess the reason is oxidative decomposition of proteins from whatever source (cobwebs falling in, skin, etc.).
Tim
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YT2095
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| Quote: | Originally posted by 12AX7
I would have to guess the reason is oxidative decomposition of proteins from whatever source (cobwebs falling in, skin, etc.).
Tim |
Welcome to the Dungeon! *Cough* I mean Lab
\"In a world full of wonders mankind has managed to invent boredom\" - Death
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woelen
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| Quote: | Originally posted by 12AX7
My NaClO3 inevitably has a slight fishy/musty odor. I don't know if it's necessarily an amine, or at least a simple alkylamine. I would have to
guess the reason is oxidative decomposition of proteins from whatever source (cobwebs falling in, skin, etc.).
Tim |
How do you store your chemicals? My chemicals are stored in such a way that not a single animal-source material can get into the chemicals. I put a
big sign, "forbidden for spiders" on every bottle .
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12AX7
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I keep them in jars or zip-lock bags (and the oxidizers in a steel can). But that doens't matter here; the smell has been in the stuff since it was
crystallized, so it must've been in the liquor. I don't cover my chlorate solutions, and I have been known to stir them by hand.
That said, it's weird that my potassium chlorate is more or less odorless.
As far as bugs obeying my labels, I let them learn the hard way. I do have a few jars of nasty yellow or green or whatever solutions with a bug of
some sort floating in it...
Tim
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UnintentionalChaos
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12AX7- I think the one time I left a lead acetate solution uncovered overnight, 10 flies managed to drown in it. I keep paper towels or tissue taped
over everything while evaporating nowadays.
YT2095- You say that KMnO4 has a dry smell. As larger crystals, yes it has not much of a smell, but I was refrring to accidentally inhaling very fine
particles resulting in a smell being formed by oxidation occuring inside my nose. The larger crystals I was grinding didn't have any specific odor
I keep most of my stuff in old HDPE containers from medicines and vitamins. I've found that the screwcap canisters my NaOH comes in (after I use it
all) are rather airtight (as they have to be). They however, hold about 3 pounds of a medium density salt. They've kept anhydrous MgSO4 nice and dry
for months now.
Department of Redundancy Department - Now with paperwork!
'In organic synthesis, we call decomposition products "crap", however this is not a IUPAC approved nomenclature.' -Nicodem
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chloric1
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@ Madhatter-Come think of it, yes nitrates do have a distinctive odor. It is most probably nitric acid with a metalic note which sweetened it. I
theorize free nitric acid as the smell seems to follow the salt with more hydrolitic activity. For example, it is much more noticeable from my bottle
of ferric nitrate as apposed to cobalt nitrate. Simularly lead nitrate is more aromatic than calcium nitrate etc. In time though, many nitrates;
exempt, sodium, potassium, and ammonium, lose some nitric acid and become partially basic if left in adverse climatic conditions. I have even seen
brown calcium nitrate!
@tim- The amine contamination thing would scare me. Especially with the amount of chlorate you keep I have only generated 700 or 800 grams if I am lucky. I hope when I dry it I don't lose too much weight. If you
continue to notice weird odors in your chlorate, then take a single crystal about the size of a pea dissolve in very pure water in a test tube and
test its pH! If it is acidic you might have a ticking time bomb waiting for just the right contaminate to come down the pike. Acidic chlorates
release chlorine dioxide with, sugars, alcohols,aldehydes,ketones ammonia, urea etc. You get the idea.
Fellow molecular manipulator
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