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Ioxoi
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Favorite Crystal Growing Chemicals
Hi everyone,
I was just wondering what everyone's favorite crystal growing chemical was. Some people like the alums; others like monoammonium phosphate, copper
sulfate or even sugars.
I'm posting this because I've got a new favorite: triethanolamine hydrochloride! I'm not a "pro crystal grower" (if that title even exists) by any
means, but I think some of the really good ones out there should experiment with this chem and see what kinds of results they can get. I've pulled out
some absolutely fantastic crystals out of some waste solution growing in one of my mom's plates that put crystals of other chemicals I've purposely
tried to grow to shame.
As far as I've been able to tell, the most basic crystal shape (single crystal) is like the right angle prisms found in binoculars. I have one
flawless crystal (it has a small internal striation, though) and when you look at it up close, it's unbelievable how perfectly smooth it's shape is.
It actually looks like an acrylic prism from a precision optical device, except shrunk down to a couple mm on a side! I've also gotten some bigger
clusters, but again they were growing in a dish unintentionally so I'm sure other guy out there could get much better results.
The main reason I like them better than others is
1. They're perfectly clear and
2. They're really stable. They don't dehydrate and turn opaque and they don't liquefy in humid air as far as I've been able to tell. I don't think
they even form a hydrate at all.
You can make it in mass by buying a gallon of TEA from the ChemistryStore.com and then adding a big excess of muriatic acid. You can filter and dry
the crystals (careful, heat makes solution outgas HCl) or just dilute the slurry down until it dissolves and use that as a crystal solution.
Anyone got any other favorites?
Chuck Norris does not uphold laws. He is the law.
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Nick F
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I haven't tried it yet, but I'm going to try putting a sat. cobalt chloride solution into a vacuum desiccator. I hope that this will speed up crystal
formation, while still making it slow enough for nice crystals to form. I just really love the colour of that compound! Then I'll probably seal it in
something to keep it stable (maybe even cast it in some crystal-clear acrylic resin that I have to make a nice paperweight!).
Large potassium dichromate crystals are beautiful too, but apparenly they're not very easy to grow. And some lanthanide sulphates have nice colours.
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12AX7
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Incidentially, sodium bromate hydrate (monohydrate I believe) typically forms platelike crystals, reminiscient of BaCl2.2H2O and mica. Unfortunately
they are air sensitive (turning white in this dry winter air).
It also forms thin crystals, probably the same habit but finer, when a boiling-hot solution is cooled with few nucleation sites. I had hot filtered a
solution, half a day later discovering that it had congealed into a radiant suspension. Fortunately, such a suspension is easy to break up, because
sodium bromate appears to have a relatively small solubility difference with temperature (indeed, a saturated solution at 15C is quite concentrated).
Tim
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Magpie
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Earlier in this thread YT2095 shows nice pictures of copper acetate he made. I presume this is cupric acetate.
I am attempting to make same, but I think my synthesis is going bad and I'm getting Cu(OH)2 instead. Here's what I did:
I reacted stoichiometric amounts of of Ca(OH)2 and white vinegar (5% HOAc) to form Ca(OAc)2 in lots of water. Then I added a stoichiometric amount
of CuSO4*5H2O.
Ca(OAc)2 + CuSO4*5H2O --> Cu(OAc)2 + CaSO4*2H20 +3H2O
The gypsum was then removed by filtration, which is not hard when using a little diatomaceous earth added and a Buchner funnel.
Then I placed this navy blue translucent solution, which I assume to be aqueous Cu(OAc)2, on a hotplate-stirrer to evaporate off the water. But, it
turned into a light blue slurry upon heating and vapors smell strongly of acetic acid. Hence my assumption that I'm forming a Cu(OH)2 slurry out of
my dilute Cu(OAc)2. Right?
Now my question for YT2095: How please did you make your nice dark green crystals? 
And, if anyone else can offer a method for making the Cu(OAc)2 please do. I searched but could not find one.
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UnintentionalChaos
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Why even bother with the messy calcium step? Use dilute NaOH and make Cu(OH)2 (carbonate, bicarbonate (some carbonato complex will exist solvated no
matter what so don't expect the liquid to go colorless) or even very slow careful addition of ammonia, stopping when the ppt. begins redissolving as
dark blue tetraamminecopper (II) ions) from your CuSO4, filter out and wash the ppt. then dissolve in HOAc. Boil down, with an excess of acetic acid
until the solution is intensely dark blue and chill down as much as possible without freezing and keep it there for a few hours (It doesn't mind
hanging out supersaturated while crystals slowly form), collect crystals, then boil down again (I found a little more than halving the remaining
solution worked out well.
Your slurry is likely calcium sulfate which has a nasty habit of easily forming supersaturated solutions and slowly crystallizing out (happened when I
did an analagous procedure using CuSO4 and CaCl2). The boiling probably agitated it enough to force at least some of it to crystallize out.
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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garage chemist
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Or even better, use CuO for reaction with the acetic acid- it's way easier to filter than Cu(OH)2 and has a stochiometric composition and no water of
hydration.
Just heat the Cu(OH)2 suspension from CuSO4 and NaOH until completely black and the CuO begins to settle.
I thought you had some pure acetic acid by now, Magpie? Why are you using vinegar?
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Magpie
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GC, that method looks very straight forward.
| Quote: |
I thought you had some pure acetic acid by now, Magpie? Why are you using vinegar?
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Because I am a skinflint. 
And thanks Un. Chaos for the insight on the CaSO4 formation. I guess that batch is toast. 
Maybe not toast. I turned off heat, let it cool, then turned off stirrer. White solids (CaSO4) quickly settled out leaving a dark blue translucent
supernate with no apparent Cu(OH)2 ppt gel. pH is slightly acid. So maybe some Cu(OAc)2 is recoverable here. I will filter again and go from there.
[Edited on 16-4-2008 by Magpie]
[Edited on 16-4-2008 by Magpie]
[Edited on 16-4-2008 by Magpie]
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chemoleo
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| Quote: | | I'm posting this because I've got a new favorite: triethanolamine hydrochloride! I'm not a "pro crystal grower" (if that title even exists) by any
means, but I think some of the really good ones out there should experiment with this chem and see what kinds of results they can get. I've pulled out
some absolutely fantastic crystals out of some waste solution growing in one of my mom's plates that put crystals of other chemicals I've purposely
tried to grow to shame. |
Just now I wanted to write, triethylamine HCl doesn't crystallise well (as I've found that it forms needles which are very hygroscopic) and dang,
there it is, you are writing on triETHANOLamine HCl
Where did you get the triethanolamine from?
On the matter of CuAc2 - I've made liters of the stuff using this very method, with CaSO4 - CaCO3 was dissolved in 25% HAc until it would dissolve no
more, and to this the calculated amount of CuSO4 was added. This was filtered, rinsed more with cold H2O until the CaSO4 on the filter went pale green
blue. The supersaturated solution started crystallising finest CuAc2 in no time, as glittering dark green crystals, which were so small that it was
essentially a powder that could be filtered off and dried. It keeps well for several years. The CuAc2 at the time was used to produce lead acetate
with Pb metal.
Anyway, I'd perhaps omit the boiling step, and work right away with highly concentrated solution. THat should allow you to filter off a significant
amount of beautiful pure CuAc2.
Never Stop to Begin, and Never Begin to Stop...
Tolerance is good. But not with the intolerant! (Wilhelm Busch)
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DJF90
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Potassium triethanedioxatoferrate (III) crystals are bright green, and looked spectacular. I can remember making some at school when we were learning
about transition metals, shame I didnt take any pictures Anyway heres the equation
if anyone wants it:
FeCl3 + 3K2(C2O4) => K3[Fe(C2O4)3] + 3KCl
Basically we made weighed out stoichiometric amounts of the Iron (III) chloride and the Potassium oxalate. The FeCl3 was dissolved in half of the
amount of water as the Potassium oxalate, and the two resulting solutions were mixed in a small beaker and covered. Unfortunately I have a feeling
that the compound may be light sensitive, as the textbook has made the note "leave a sample exposed to sunlight or powerful light".
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UnintentionalChaos
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The above compound would be more easily understandable if named as potassium trisoxalatoferrate (III). Here's something that popped up on google about
photosensetivity... http://adsabs.harvard.edu/abs/1975JSSCh..12...92S
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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DJF90
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Sorry theres a typo... It's potassium triethanedioatoferrate (III), not triethanedioXatoferrate (III). It is equally understandable, its just that
instead of naming it using the traditional name (oxalate), its named using the IUPAC accepted name (ethanedioate). Sorry for any confusion caused by
my typo.
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Magpie
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re: Cu(OAc)2 from vinegar, Ca(OH)2, and CuSO4*5H2O
I filtered off the second crop of CaSO4 then placed the filtrate in 2 shallow dishes appropriated from the kitchen, w/permission. This morning there
were hundreds of very small dark crystals forming evenly all over the bottom of the dishes.
This procedure does have its drawbacks in dealing with the CaSO4 ppt. The best removal of this most likely would be done when the suspension is near
boiling due to CaSO4*2H2O retro solubility with temperature.
[Edited on 17-4-2008 by Magpie]
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YT2095
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| Quote: | Originally posted by Magpie
Now my question for YT2095: How please did you make your nice dark green crystals? |
I made a vinegar soln with GAA and tap water (roughly a 10% soln).
I then simply dissolved copper carbonate into it until all the Fizing stopped and some carbonate was left unreacted.
this was then filtered into a beaker and left to evaporate on a warm power transformer.
it took about a week to be be completely crystalised in the way you see in the pictures I posted.
\"In a world full of wonders mankind has managed to invent boredom\" - Death
Twinkies don\'t have a shelf life. They have a half-life! -Caine (a friend of mine)
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Magpie
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Thanks YT2095 for the method on your large crystals.
Mine have been growing for about 2 days now. I have two shallow dishes sitting in a window (eastern exposure) to warm in the morning sun as shown.
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Magpie
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My cupric acetate is nearly finshed crystalizing. Upon examination I find quite a bit of contaminating crystals that formed right at the end. They
are clear needles and I assume that they are calcium acetate. There is also a gummy material mixed in with the crystals. I suppose this is the
sugars/misc organics that come in with the vinegar as mentioned in another thread. So I can't really recommend this method. Next time I will use the
method recommended by garage chemist, especially with regard to using GAA instead of vinegar.
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16MillionEyes
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I tried making Cu(AcO)2 the stupid way ( NaAcO + CuSO*5H2O) and although I did get very few dark colored crystals they seem to be more a matter of odd
luck than an actual process. What I do get in relatively copious amount though, is some light turquoise solid that is just slightly less soluble than
the CuSO4 or the NaSO4 so that it forms a thin layer on the bottom of the beaker. I don't know what it is although I suspected it to be Cu(AcO)2
before seeing actual pictures (some sites described it as what I have so I felt confident). Hopefully someone can tell me.
[Edited on 21-4-2008 by __________]
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12AX7
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Could it be a I,II compound salt perhaps?
Crystallizing ternary mixtures like that can be a bitch. Instead of fractional crystallization, you're probably better off precipitating the
important stuff (e.g., NaOH giving Cu(OH)2 and NaOAc and Na2SO4 in solution) and starting over. Outside chance you could seperate one or two phases
from the dried, ground product with another solvent.
Tim
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16MillionEyes
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I took a picture of it, for a while I did consider it being a Cu(I) salt but I have no way of confirming it. One thing I did notice though, the
solution smells strongly of acetic acid and I can't see why it should.
Any ideas?
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YT2095
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that Almost looks like the copper carbonate I start with 
\"In a world full of wonders mankind has managed to invent boredom\" - Death
Twinkies don\'t have a shelf life. They have a half-life! -Caine (a friend of mine)
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woelen
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This green stuff is a basic acetate, or a mix of basic acetate and basic sulfate.
NaOAc partly hydrolyses, because HOAc is a weak acid:
Dissolving: NaOAc --> Na(+) + OAc(-)
Hydrolysis: OAc(-) + H2O <---> HOAc + OH(-)
The hydroxide ions, formed in this hydrolysis reaction, precipitate with the copper(II) ions. No true Cu(OH)2 is formed, but a mixed Cu(OH)(OAc) salt,
or a mix with sulfate ions as well. The remaining solution most likely is quite acidic and smells of vinegar.
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16MillionEyes
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I see, thanks. I did imagine the acetate was deprotonating the water and thus forming the hydroxide, the problem was I couldn't picture where the
hydroxide would go so I didn't know exactly how to explain the vinegar smell. Now that you mention the possibility of a basic acetate it makes sense.
Anyhow, is this stuff good for anything useful/interesting?
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chemoleo
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For the record, here's a picture of triethylamine hydrochloride...not a good target for growing nice crystals
[Edited on 13-5-2008 by chemoleo]
Never Stop to Begin, and Never Begin to Stop...
Tolerance is good. But not with the intolerant! (Wilhelm Busch)
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12AX7
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Nice picture of what looks like awful crystals! Pointy and thin, like urea. Man, I'm recrystallizing urea, my fingers keep getting poked when I stir
around in the solution!
Tim
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The_Davster
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Also has remarkable resemblance to the crystals of phenol which grow under the cap by sublimation.
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12AX7
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Ah, indeed! Only, those are fucking impossible to scrape off the sides! ARGH!
Tim
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