ScienceHideout
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Turn Mcrs Chloride to Mcrc Salts?
I am a bit curious- I want to use my mercurous chloride in a reaction- but- it doesn't dissolve (as you already know).
To make this "poisonous garbage" useable, is there anything that I can do to make it a nice mercuric salt. I tried to see if I could react it with a
mineral acid- I tried HCl and H2SO4, and after failing, I thought I'd ask you.
And I don't want to decompose it with light.
Before you post- I don't need the usual "Mercuric Salts are too dangerous for a home chemist" because I don't plan on eating it- I plan on keeping it
in a locked cabinet until it should be used for an experiment I will conduct IN MY HOOD with a face shield, goggles, and gloves.
hey, if you are reading this, I can't U2U, but you are always welcome to send me an email!
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turd
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Oxidation with H2O2, KMnO4, K2CrO4, K2Cr2O7 or aqua regia? Also I think it should react with hot conc. H2SO4 to give HgSO4, which can be dissolved in
acidic solution. Conc. HNO3 should work as well. Or disproportionate with NH4OH (there is no Hg2O!) and dissolve in hot conc. H2SO4.
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Neil
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Playing with Hg and you haven't even looked at the wiki page for the compound you are using?
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ScienceHideout
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My teachers always say
"Wikipedia can't always be reliable"
I could edit the wiki page for Lead Acetate and put it as a non-poisonous substitute for sugar- and say it has no effective dose! 
hey, if you are reading this, I can't U2U, but you are always welcome to send me an email!
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Bot0nist
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Sigh... If you use wiki right, and find supporting sources, you have nothing to fear from stupid spoofs like that.
U.T.F.S.E. and learn the joys of autodidacticism!
Don't judge each day only by the harvest you reap, but also by the seeds you sow.
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Neil
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No, you are right; Wiki is not to be taken without a salt shaker or two but as a start point it normally provides a link to a MSDS for whatever
chemical it has an entry for and in your case it provides the data which was essentially summarized by Turd.
The data could have been followed up on and verified all of which would be a very good idea if you are to work with a substance so lingeringly toxic
as mercury. I assume your teachers also point out that reading something on a forum doesn't make it any more reliable? 
Edit: Bot0nist got there first...
[Edited on 24-10-2011 by Neil]
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ScienceHideout
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I would much rather trust everyone here better than the spoofs of Wikipedia. I remember once I was doing research, and someone added an extra word to
Avogadro's name. I forgot what it was... DeCamillo or something like that...
Anyways, I also feel that lots of people exxagerate the toxicity of Hg... they make it sound like it is worse than benzene- this contact poison
reputation. In fact, I could bet all of our grandparents used to PLAY with it for the fun of it! They were all fine!
hey, if you are reading this, I can't U2U, but you are always welcome to send me an email!
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Neil
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...metallic mercury and the salts of mercury are a little different
Ie metallic mercury embolism - The Wiz posted this somewhere;
http://circ.ahajournals.org/content/91/12/3020.full
Vs the salts
Mercuric chloride
Toxicological Data on Ingredients: Mercuric chloride: ORAL (LD50): Acute: 1 mg/kg [Rat.]. 6 mg/kg [Mouse]. DERMAL
(LD50): Acute: 41 mg/kg [Rat].
http://www.sciencelab.com/msds.php?msdsId=9924616
Mercuric nitrate monohydrate
Toxicological Data on Ingredients: Mercuric nitrate monohydrate: ORAL (LD50): Acute: 26 mg/kg [Rat]. DERMAL (LD50):
Acute: 75 mg/kg [Rat].
http://www.sciencelab.com/msds.php?msdsId=9924618
methylmercuric chloride
Toxicology
Very toxic by inhalation, ingestion and through skin contact. Danger of cumulative effects. Note low LD50s.
Toxicity data
(The meaning of any abbreviations which appear in this section is given here.)
ORL-GPG LD50 21 mg kg-1
IPR-RAT LD50 11 mg kg-1
IPR-GPG LD50 7 mg kg-1
IPR-MUS LD50 17 mg kg-1
ORL-MUS TD50 1.91 mg/kg/day.
http://msds.chem.ox.ac.uk/ME/methylmercury_chloride.html
I'd much rather trust most of the people here then wiki sans verification but I would still never mix X with Y until I had independently verified
whatever was said.
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hkparker
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Mercury as an element likes to stick to itself a lot, and therefore doesn't penetrate skin well, so short contact will almost never cause long term
damage. Now what you are trying to make is a soluble mercury salt, which is much much more toxic. A soluble mercury salt could be much more easily
absorbed through skin.
<a target="tab" href="http://en.wikipedia.org/wiki/Karen_Wetterhahn">An extreme example of how mercury can be extremely toxic</a>.
The salts you are trying to make will not be that toxic of course but that give you an idea of how the toxicity of an element does not speak for its
compounds. You can look up the values for toxicity on an MSDS sheet. Look for a value called "LD<sub>50</sub>". This is the amount (in
mg/Kg of body weight most of the time) that would be needed to kill 50% of a population. For example, NaCl has an LD<sub>50</sub> of just
about 3000mg/Kg.
Benzene = 930mg/Kg[oral/rat].
Phenol = 317mg/Kg[oral/rat].
Mercuric Nitrate = 26mg/Kg[oral/rat].
Mercuric Chloride = 1mg/Kg[oral/rat].
Pretty big difference between benzene and mercuric salts.
There are similar measurements such as LC<sub>50</sub> for gasses (lethal concentration for 50% population kill) and those usually have a
time in their units as well.
Also, if you pay attention to what has a source on wikipedia, it can be extremely useful. The idea that wikipedia is useless is very misinformed.
http://avogadro.chem.iastate.edu/MSDS/phenol.htm
http://www.sciencelab.com/msds.php?msdsId=9927339
http://www.sciencelab.com/msds.php?msdsId=9924618
http://www.sciencelab.com/msds.php?msdsId=9924616
EDIT: Neil beat me to it
[Edited on 25-10-2011 by hkparker]
My YouTube Channel
"Nothing is too wonderful to be true if it be consistent with the laws of nature." -Michael Faraday
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woelen
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HgCl can be converted to a solution of HgCl4(2-) ions by adding concentrated HCl to it and then adding 30% H2O2. All of the HgCl will dissolve slowly.
Don't add the H2O2 at once, but add this in small amounts, otherwise you'll end up with a lot of foam and a plume of oxygen/chlorine mix. If the
dissolving of the HgCl is slow, then heat the liquid, such that it just does not boil.
The concentrated acid and H2O2 can be boiled off, but this MUST be done in a fume hood or outside. The fumes of HCl and Cl2 are bad enough already,
but almost certainly some HgCl2 will volatilize as well, so know what you are doing. I personally do not recommend the boiling down of this liquid
until solid HgCl2 appears. There is too much risk of poisoning yourself.
Another much safer option is to keep the mercury(II) in solution and use that solution for experiments. In order to achieve this you need to heat for
a while and boil for a few minutes. This destroys all remains of H2O2 and makes the liquid just acidic. You can add a 10% solution of NaOH to
neutralize the acid and the solution then can be used as is for experiments with aqueous HgCl2. The additional NaCl hardly interferes with most
experiments.
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turd
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I've never seen it written like that. Hg<sup>+</sup> is practically always written as Hg<sub>2</sub><sup>2+</sup>.
On the other hand nobody ever writes P<sub>4</sub>O<sub>10</sub>.
If the original poster failed to dissolve Hg2Cl2, I can only assume that he didn't really try.
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woelen
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You are right about HgCl, it is much better to write Hg2Cl2. The ion Hg(+) does not exist, it is Hg2(2+).
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mr.crow
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I like the H2O2 oxidation idea, seems much better than adding nitric acid
If you want something to do with your HgCl2 try adding excess KI solution to precipitate the very pretty and insoluble HgI2
Clean up any mercury waste with sodium polysulfide solution. Of course you should have good lab skills to do this
Double, double toil and trouble; Fire burn, and caldron bubble
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woelen
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The use of KI is an option, but assure that not too much iodide is added. If you add too much iodide, then the brilliant scarlet precipitate
redissolves again and a complex ion is formed.
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mr.crow
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Good point, forgot about that
A slight excess of iodide ions will further reduce the solubility (common ion effect)
Double, double toil and trouble; Fire burn, and caldron bubble
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woelen
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There is another very funny thing about the scarlet-red HgI2. When it is formed initially, then it is yellow and it turns scarlet-red in one or two
seconds or so. The change of color also is very nice to see.
http://woelen.homescience.net/science/chem/exps/hgi2/index.h...
On careful heating the compound also turns yellow and when it cools down then it remains yellow, until it is agitated mechanically, e.g. by strong
shaking or crunching. With silver(I) and copper(I) ions also very interesting compounds can be made.
http://woelen.homescience.net/science/chem/exps/hgi2_thermoc...
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turd
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| Quote: |
In the first experiment, there first is a gradual change of color (which also is not really striking) and at a certain temperature, there is a
sharp transition from one color to another. On cooling down, the color does not simply revert. It really seems as if a new compound is formed.
In the other two experiments, there is a gradual change of color with temperature. When temperature increases, then a certain color change occurs
and when temperature decreases again, then changes occur in reverse order. For each temperature, there is a color, and the color does not depend on
the history of heating.
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This is not very surprising. First order phase transition: Sudden change, hysteresis. Second order phase transition: smooth change of order parameter,
no (or little) hysteresis. I've seen first order phase transitions where you could get the low temperature phase only by prolonged heating slightly
below the phase transition temperature.
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