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bfesser
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Quote: Originally posted by bfesser  | <strong>CuSO<sub>4</sub>(aq) + 2 NaHCO<sub>3</sub>(aq) → Cu(HCO<sub>3</sub> <sub>2</sub>(s) +
Na<sub>2</sub>CO<sub>3</sub>(aq)</strong> |
I can't believe nobody spotted my
error. Sodium carbonate; what? I guess nobody bothers to read my longer posts.
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bbartlog
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Oh, I read it. But it's easy to skim over a description like that when you already know what's being discussed.
The less you bet, the more you lose when you win.
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Doktor Klawonn
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Tetra amine copper (II) nitrate, [Cu(NH3)4](NO3)2
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Lion850
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I recently made tetraamine copper (ii) sulphate:
- 20g CuSO4.5H2O in 65g water in a beaker, stir and heat a bit to get all dissolved
- Add 19g of 28% ammonia solution. A light blue suspension formed which quickly redissolved into a dark solution. Total solution volume just under
100ml.
- Continue stirring 15 minutes.
- Add 4 batches of 25ml 99% ethanol, total 100ml added.
- Dark bottom layer, clear top layer, some crystals on sides of beaker.
- Stir 5 minutes and then put aside for 5 hours.
- Blue solution with dark blue lower layer.
- Gravity filter and rinse with ethanol in funnel. Dark blue remainder, light blue filtrate.
- Press remainder dry between filter papers and paper towel
- Leave on bench overnight.
- Next morning: product has slight ammonia smell.
- Dry under a steel dish in hot sun for one hour.
- Bottled 18g of dark blue-purple crystals. Photo below.
Question: How much alcohol to add to force the crystals out of the (water) solution? I added an equal amount as the volume of the water solution as I
had no clue. This seemed to have worked, but I dont know whether this was excess or maybe not enough.
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artemov
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| Quote: Originally posted by Lion850 | I recently made tetraamine copper (ii) sulphate:
- Stir 5 minutes and then put aside for 5 hours.
- Blue solution with dark blue lower layer.
- Gravity filter and rinse with ethanol in funnel. Dark blue remainder, light blue filtrate.
- Press remainder dry between filter papers and paper towel
- Leave on bench overnight.
- Next morning: product has slight ammonia smell.
- Dry under a steel dish in hot sun for one hour.
- Bottled 18g of dark blue-purple crystals. Photo below.
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Do you have a problem with it losing ammonia and changing color?
Is it blue or purple? I am trying to make a purple salt for my rainbow salts series 
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Lion850
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Hi Artemov it was made only 2 days ago, so far the color seems to stay the same. In an open dish there was a very slight ammonia smell, now that it in
a sealed small bottle I will have to see what happens. I think it is more of a dark blue than a purple.
Look at the below photo. All different copper cyanurates. The middle bottle is to me a beautiful deep purple colour and it has kept its colour for
months now.
I look forward to see your rainbow!
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artemov
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| Quote: Originally posted by Lion850 |
Look at the below photo. All different copper cyanurates. The middle bottle is to me a beautiful deep purple colour and it has kept its colour for
months now.
I look forward to see your rainbow!
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Thanks thanks ... is it from the reaction with NaDCC? Unfortunately I have no access to that. I am thinking of hexaamminenickel for my purple. Still
contemplating on the Red, Orange, Yellow, Green and Blue 
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Lion850
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Have a look at this thread for info on the cyanurates:
http://www.sciencemadness.org/talk/viewthread.php?tid=155624
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artemov
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Wow thanks. I especially love the color of the copper powder + cyanuric acid combi, and the well known NaDCC one 
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DraconicAcid
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| Quote: | Do you have a problem with it losing ammonia and changing color?
Is it blue or purple? I am trying to make a purple salt for my rainbow salts series |
Tetramminecopper(II) is fairly stable- I've had samples for years that haven't lost any ammonia. It's not like hexamminenickel(II).
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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Fery
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Artemov you can buy it as swimming pool tablets, just look thouroughly into specification as sometimes TCCA is used and sometimes NaDCC. I found them
easily by searching my country code and the compound name like
cz sodium dichloroisocyanurate bazen
bazen = swimming pool in my language
We used it also as water disinfectant in army when training in wild nature when the only available water was from natural sources with expected
microbial contamination.
https://www.sciencemadness.org/whisper/viewthread.php?tid=56...
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artemov
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| Quote: Originally posted by DraconicAcid |
Tetramminecopper(II) is fairly stable- I've had samples for years that haven't lost any ammonia. It's not like hexamminenickel(II).
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Darn 
| Quote: Originally posted by Fery | Artemov you can buy it as swimming pool tablets, just look thouroughly into specification as sometimes TCCA is used and sometimes NaDCC. I found them
easily by searching my country code and the compound name like
cz sodium dichloroisocyanurate bazen
bazen = swimming pool in my language
We used it also as water disinfectant in army when training in wild nature when the only available water was from natural sources with expected
microbial contamination.
https://www.sciencemadness.org/whisper/viewthread.php?tid=56...
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Thanks Fery, beautiful pics!
We have TCCA here, I bought some, but not pure NaDCC.
I bought some effervescent disinfectant tablet with NaDCC (400mg per tablet), but the "effervescent" part also precipitated a non-blue/purple copper
compound in large amount, overwhelming my copper-sodium-dcc complex.
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DraconicAcid
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| Quote: |
You're disappointed that the colour stays nice? |
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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artemov
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No, cos I need a purple salt (in this case would be the hexaamminenickel)!
[Edited on 8-12-2020 by artemov]
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DraconicAcid
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| Quote: Originally posted by artemov |
No, cos I need a purple salt (in this case would be the hexaamminenickel)!
[Edited on 8-12-2020 by artemov] |
The tris(ethylenediamine)nickel complex is extremely stable (I tried heating it once to nearly 200 oC, and no sign of decomposition). I have some
gorgeous crystals of [Ni(en)3]C2O4 that I grew by vapour diffusion of isopropanol into an aqueous solution of the salt.
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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artemov
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| Quote: Originally posted by DraconicAcid |
The tris(ethylenediamine)nickel complex is extremely stable (I tried heating it once to nearly 200 oC, and no sign of decomposition). I have some
gorgeous crystals of [Ni(en)3]C2O4 that I grew by vapour diffusion of isopropanol into an aqueous solution of the salt. |
Thanks, but I have no access to en ...
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Bezaleel
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| Quote: Originally posted by DraconicAcid |
The tris(ethylenediamine)nickel complex is extremely stable (I tried heating it once to nearly 200 oC, and no sign of decomposition). I have some
gorgeous crystals of [Ni(en)3]C2O4 that I grew by vapour diffusion of isopropanol into an aqueous solution of the salt. |
Vapour diffusion of isopropanol into an aqueous solution. Could you describe your setup? Feels like I have a learning moment ahead
of me
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MidLifeChemist
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I'm in California, I've looked and looked for pure or fairly pure NaDCC but can't find any at all... my only options seems to be to buy some from
Europe, but it is not that cheap.
if anyone in the US has a better idea please let me know. I have seen some tablets but they don't seem to contain much NaDCC but they do have lots of
unknown impurities.
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DraconicAcid
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I took a jar and put some isopropanol in it. I put a small beaker, one-third filled with an aqueous solution of the salt, and put it in the jar. Put
the lid on the jar, and let it sit for a week or so. The isopropanol evaporates from the jar and slowly diffuses into the aqueous solution, lowering
the solubility of the compound, so it slowly crystallizes out.
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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artemov
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| Quote: Originally posted by Bezaleel | | Vapour diffusion of isopropanol into an aqueous solution. Could you describe your setup? Feels like I have a learning moment ahead of me |
What DA described above.
https://web.mit.edu/x-ray/cystallize.html
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itsallgoodjames
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| Quote: Originally posted by DraconicAcid | | Quote: | Do you have a problem with it losing ammonia and changing color?
Is it blue or purple? I am trying to make a purple salt for my rainbow salts series |
Tetramminecopper(II) is fairly stable- I've had samples for years that haven't lost any ammonia. It's not like hexamminenickel(II).
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It's what? I've had a sample for a few months, and it's already noticably lighter in color. It also reeks of ammonia when I open the container it's
in. Attached is a picture of just after I made it. I'm not home right now, so I can't take a picture of it now, but it is quite a bit lighter. Is
one supposed to store it in solution or something?
Nuclear physics is neat. It's a shame it's so regulated...
Now that I think about it, that's probably a good thing. Still annoying though.
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DraconicAcid
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I just checked a jar I made a decade ago. Still looks the same.
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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woelen
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My experience with tetramminecopper(II) is that it can be kept indefinitely, but it must be stored in a really tightly sealed container. I put some of
its perchlorate salt in a glass ampoule, and this still looks the same as when I made it (several years ago).
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artemov
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| Quote: Originally posted by woelen | | My experience with tetramminecopper(II) is that it can be kept indefinitely, but it must be stored in a really tightly sealed container.
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What about hexaamminenickel(II)?
My synthesis of tetraamminecopper(II) sulfate -
Pic 1: 22.5g of CuSO4.5H2O (dissolved in 80g of H2O) and 35g of NH4HCO3 (23% molar excess).
Pic 2: NH4HCO3 is slowly added to CuSO4 solution, vigorous effervescence (CO2?) with thick light blue ppt. No smell of ammonia.
Pic 3: Solution turning a darker shade of blue as more NH4HCO3 is added.
Pic 4: Solution eventually turned deep dark blue with no ppt. Put on hot water bath to about 60-70 C to expel gases. Slight smell of ammonia near the
end.
Pic 5: About 100ml of methanol added, cooled, filtered and washed with 50ml of cold methanol. Deep dark blue solid obtained, in drybox with CaCl2.
    
[Edited on 10-12-2020 by artemov]
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Bezaleel
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| Quote: Originally posted by DraconicAcid | | I took a jar and put some isopropanol in it. I put a small beaker, one-third filled with an aqueous solution of the salt, and put it in the jar. Put
the lid on the jar, and let it sit for a week or so. The isopropanol evaporates from the jar and slowly diffuses into the aqueous solution, lowering
the solubility of the compound, so it slowly crystallizes out. |
Thank you both, that's completely clear.
I had never heard of this method, although I am familiar with the rough method: adding ethanol (for example) to force a salt to crystallise from
water. Once used it to quickly obtain PrCl3.nH2O. It showed a very special visual effect when the green droplets fell to the bottom of the tube.
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