16MillionEyes
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Copper(II) Chloride
I've been looking at different sources that talk about the high toxicity of this compound. The thing is that I made some of it myself and been
handling it like salt water. Do you guys know if it's all that "dangerous"? I know sites like to overemphisize on harmful effects but should I really
be concerned if I'm just careful with it?
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not_important
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What sources are these? It's rated as a 2, care should be taken but it's not an extreme toxin. The LD50 is several hundred mg/kg https://fscimage.fishersci.com/msds/05625.htm
Chronic toxicity is more of a worry than acute, avoid long term exposure to copper salts as even fairly low levels will interfere with metabolism.
This is true for many metals, they are needed in some amount but larger amounts interfere with utilization of other essential metals, screwing up
enzymes.
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16MillionEyes
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I used that very same source in fact (I just looked at Cu(II)Cl2 anhydride though). If you read through it you see that they in fact keep pointing out
harmful effects and measures that should be taken etc etc.
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not_important
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MSDS information is in part a legal defense along the lines of "we told you not to pour flammable liquids on yourself and ignite them. You ignored our
advice, tough luck, you can't sue us."
Are you eating it? Make dust out of it and breathing it in? Rubbing it on your skin or immersing your hands in solutions of it for extended periods?
Do you work with it for hours each day, for weeks and weeks? If not then you're not likely to have trouble.
Not that people have worn copper jewelry, which is exposed to air plus salt and organic acid from sweat, since prehistoric times without a lot of
cases of copper toxicity.
So wash your hands when done working with it, avoid a lot of contact with it - even cheap food handling gloves would work if you're worried, and if
you're using it dry as a fine powder avoid inhaling the dust.
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woelen
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Very good advice from not_important, this is how I like it. Let's use common sense and not be chemophobes. Of course, you must not eat, drink, or
smoke while working with chems, you must not expose yourself (skin) too much to the chem, but for the rest, don't worry too much.
I want to add one thing: The only really important thing is that you must take care not to contaminate your house with chemicals. Only experiment at
one place and clean up spills, glassware and tools immediately after the experiment is done. Long-term low-level exposure, due to contamination of
your entire house is a serious risk, but this can easily be avoided with some hygiene and common sense.
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16MillionEyes
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I wish I could do so and trust me I would certaintly do it. Problem is I live in an apartment, I do things in the kitchen. This reaction though, was
done under safe conditions so I'm really not to worried although I wish I could keep reactions in one place and food in other (as I always try
anyway). I was just wondering because sites tend to overdramatize things and sort of got to me and just wanted to make sure I wasn't being too
careless.
By the way, I dihydrated the Cu(II)Cl2 and got the expected yellowish-brown Cu(II)Cl2 anhydride, problem is that I added water and it didn't turn
blue. I know it takes time but I left it for quite a while and didn't do anything. Any ideas?
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DeAdFX
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I believe you have copper Oxychloride. Copper salts when heated partially hydrolysize. Copper oxychloride is a mixture of copper chlorides and
copper hydroxide/oxides.
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16MillionEyes
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I don't know. How could I test for that? Also, the odd part is that the same sample heated earlier and redissolved turned blue normally. What
temperature does copper hydrolize at? I'm very positive It didn't go over 110 C or so.
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12AX7
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Did it smell acidic?
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not_important
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| Quote: | Originally posted by __________...
By the way, I dihydrated the Cu(II)Cl2 and got the expected yellowish-brown Cu(II)Cl2 anhydride, problem is that I added water and it
didn't turn blue. I know it takes time but I left it for quite a while and didn't do anything. Any ideas? |
dehydrated and anhydrous Cu(II)Cl2 8-)
The meanings of anhydride and anhydrous are different.
A quick check doesn't show a decomposition temperature for the hydrated salt, just the the anhydrous form starts to decompose above 300 C.
Both are soluble in alcohol, might try that and see what happens.
You may have had a thicker layer of the solution on the surface, it's rather deliquescent, that formed a 'glaze' on the surface of the crystals as it
dried during heating, in effect making them into a few large slow dissolving lumps.
[Edited on 10-4-2007 by not_important]
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16MillionEyes
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Well, I'm not very sure about the difference between "anhydrous" and "anhydride" would you mind explaining?
What I do know is that when I heated up the hydrated Cu(II)Cl2 to the required heat (this case 100C) it turned from blue to brown (which as I've read
the brown is supposed the anhydrous hydride one of those two has to be it  ) so
I'm confident the reaction did happen. Perhaps what Deadfx suggested is what happened and got oxychlroride since the substance wasn't soluble (and
didn't turn blue as I had expected). Any ideas on how to check for sure?
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woelen
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The term "anhydrous" means without water of crystallization. This usually applies to salts, but also sometimes applies to covalent (possibly organic)
compounds or acids.
Examples:
CuSO4.5H2O is common copper sulfate, CuSO4 is the anhydrous salt
CuCl2.2H2O is common copper(II) chloride, CuCl2 is the anhydrous compound.
Frequently, the anhydrous compounds are VERY different from their hydrated counterparts. The hydrated compounds almost invariably are salts and the
anhydrous compounds frequently (not always) are mostly covalent. E.g. AlCl3 is a volatile, extremely reactive fuming solid, AlCl3.6H2O is an innocuous
white salt. FeCl3 is a black, very reactive solid, FeCl3.6H2O is the common brown/yellow PCB etching agent from electronics stores.
The term "anhydride" means that a molecule of water is taken out of a molecule (or a set of molecules) of another compound. This molecule of water did
not exist, it was created by making the anhydride.
Examples:
2CH3COOH ----- (CH3O)2O + H2O (acetic anhydride)
H2SO4 ----- SO3 + H2O (sulphur trioxide)
HNO3 + HNO2 ----- 2NO2 + H2O (nitrogen dioxide)
In the left compounds, there is no water, in the right compounds, there is water, split off from the molecules at the left. The compound at the right
is called the anhydride of the compound(s) at the left.
Anhydrides usually are extremely reactive compounds, very eager to react with water, and destroying the water in this reaction, themselves being
turned into an acid.
==========================================================
Making CuCl2 from CuCl2.2H2O must be done VERY carefully. Simply heating the hydrated solid in air results in formation of copper (II) oxide besides
anhydrous copper (II) chloride.
You have two competing reactions:
CuCl2.2H2O ---> CuCl2 + 2H2O
CuCl2.2H2O ---> CuO + 2HCl + H2O
Both reactions will occur at the same time and in practice you get a non-stoichiometric compound with formula CuOxCly, where 2x + y = 2. Ideally, you
would like to have x equal to 0 and y equal to 2, in practice, x can be as high as 0.5, meaning that you have an oxychloride compound.
You can make copper (II) chloride, anhydrous, by very slowly heating of copper (II) chloride and blowing away the water vapor immediately. I have done
that, and that works, It yields a chocolate brown solid, which becomes green on contact with water and dissolves light blue. The chocolate brown solid
is brown/yellow (mustard color), when crunched to a powdered form.
The heating must be really slow, otherwise you'll loose HCl. The starting material also must be dry nice crystals of CuCl2.2H2O. A wet puddle does not
work well, it results in a too high loss of HCl.
[Edited on 16-4-07 by woelen]
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16MillionEyes
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In that case I was using the term "anhydrous" appropiately then.
What I really had was the solution of Cu(II)Cl.22HO which I tried crystallizing by common distillation. As you might know, waters boils at 100C at
standard atmospheric preassure which makes it really hard to actually get the crystals out as hydrates and not anhydrous. I just decided to let it go
and hoped to simply apply enough water as to get the hydrated salt back. This obviously didn't happen and as someone else had already mentioned to me,
what formed was copper oxychloride. What I didn't know though is that it forms HCl and is in part responsible for the formation of the oxychloride.
Thanks for your advice anyway, I'll just make some more Cu(II)Cl2 solution and try your way, see how it works.
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tito-o-mac
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There's actually nothing dangerous about these chemicals. It's just how you take it as "dangerous" and how you deal with it.
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