Sciencemadness Discussion Board - Colorful copper compounds I've made so far

Hello all

I've been playing around with making various copper compounds and have photographed a few so far.

Perhaps the simplest to make and best saturated blue copper
chemical is "tetraamminecopper sulphate". Just add ammonia
water to copper sulphate. However, I have never tried to dry it.

Something in the back of my mind says - add a little alcohol.
I don't have time to try it now.

djh
----
The Uber liberal New York Times 28 V 11

“If he [Mladikc] goes to The Hague, he won’t last three years. He
will come back in a coffin,” said Mr. Saljic [his lawyer], who has
known Mr. Mladic since he was a military judge in 1967. “If you put
a bird in a cage you can give them whatever it wants, but it’s not
going to be happy.”

not going to be happy. Well Booo-hooo-ho.

Trifluoroacetic - 31-5-2011 at 19:33

You can buy 3% HF as Whink Rust remover. It comes in a brown bottle and can be found at most supermarkets as well as hardware stores in the US. It is pretty safe. But I would still use it in a ventilated area with rubber gloves and goggles. Nothing is worse then an HF burn to the skin, eyes, or lungs. Fluorides also cause fluorosis of the bones. The copper salt is quite safe due to it's insolubility in water.

#maverick# - 31-5-2011 at 19:33

Hello all

I've been playing around with making various copper compounds and have photographed a few so far.

ahh i love that complex, very simple and very pretty ill try the ethyl alcohol and report back

Trifluoroacetic - 31-5-2011 at 19:39

Hello all

I've been playing around with making various copper compounds and have photographed a few so far.

Ah yes copper Tetraamine sulfate. It can be crystalized from solutiont to form dark purple orthorhombic crystals if the solution is allowed to evaporate. I have found that the crystals are heat sensitive and decompose on strong heating to copper (II) Oxide.

#maverick# - 31-5-2011 at 19:49

Hello all

I've been playing around with making various copper compounds and have photographed a few so far.

wow i love that as you can see i have a thing for copper compounds

Trifluoroacetic - 31-5-2011 at 19:51

Just a note:
I made the Copper Cyanurate/ ammonia complex by reacting copper carbonate with ammonia to form the tetraamine complex; then powdered cyanuric acid was added. The complex can also be made from Copper Tetraamine sulfate and cyanuric acid but it doesn't seem to work as well.

#maverick# - 31-5-2011 at 19:58

nice nice, lets see ima start back up with making copper compounds, i got a bit distracted with some other projects in my lab

Trifluoroacetic - 31-5-2011 at 20:01

Quote: Originally posted by #maverick#

nice nice, lets see ima start back up with making copper compounds, i got a bit distracted with some other projects in my lab

Sounds like a great plan to me

COPPER IS COOL!

Trifluoroacetic - 31-5-2011 at 20:02

I made some copper II bromide which is black and upon heating it vaporizes to form a gas.

Mr. Wizard - 31-5-2011 at 20:05

Here is some Copper Phosphate, made by mixing correct molar proportions ofCuSO4.5H2O and Na3PO4. It forms a very pretty turquoise precipitate, but doesn't settle out. I let the jar sit for a few days and siphoned off the supernatant , and added fresh distilled water and mixed. I repeated this over 4 times. The final mass is very light, and was allowed to air dry slowly by covering the plastic jar mouth with a paper towel and a rubber band.

The material was to prepare an artificial turquoise when mixed with AlPO4, but other projects took over. What would be the best way to make a soluble Aluminum salt from household materials. I don't have access to Alum, which would be convenient.

#maverick# - 31-5-2011 at 20:06

yes i found a copper to copper lab, pretty simple but meh it allowed to improve some lab techniques
http://chemsite.lsrhs.net/Equations_and_Formulas/handouts/Co...

Trifluoroacetic - 31-5-2011 at 20:16

Quote: Originally posted by Mr. Wizard

Here is some Copper Phosphate, made by mixing correct molar proportions ofCuSO4.5H2O and Na3PO4. It forms a very pretty turquoise precipitate, but doesn't settle out. I let the jar sit for a few days and siphoned off the supernatant , and added fresh distilled water and mixed. I repeated this over 4 times. The final mass is very light, and was allowed to air dry slowly by covering the plastic jar mouth with a paper towel and a rubber band.

The material was to prepare an artificial turquoise when mixed with AlPO4, but other projects took over. What would be the best way to make a soluble Aluminum salt from household materials. I don't have access to Alum, which would be convenient.

I have some TSP I might have to try making Copper (II) Phosphate.

Aluminum will react with HCl H2SO4, Sodium aluminate can be made by reacting NaOH solution and aluminum metal too!

Trifluoroacetic - 31-5-2011 at 20:18

THat copper phosphate is pretty!

#maverick# - 31-5-2011 at 20:20

Quote: Originally posted by Mr. Wizard

very nice i have no Na3PO4 =(
but you can add aluminium foil to HCl and then filter to make a solution of aluminum chloride

Trifluoroacetic - 31-5-2011 at 20:24

TSP is available at most hardware stores as well as HOME DEPOT

#maverick# - 31-5-2011 at 20:27

wow im starting to lie this store even more lol i need spend more time in a lowes

Ozone - 31-5-2011 at 20:37

Nice. Have you checked out Woelen's website? He has done some fun things with Cu!

http://woelen.homescience.net/science/chem/exps/cu-redox/ind...

Cheers,

O3

#maverick# - 31-5-2011 at 20:51

yup i have thanks mate

#maverick# - 31-5-2011 at 21:33

saw this on ozone's site seemed interesting might give it a try

Dicopper (II) Acetyloxybenzoate synthesis

16, 300mg Aspirin tablets are crushed.

The resultant powder is dissolved in 100ml of a 1M Potassium Carbonate solution to dissolve the Acetylsalicylic Acid.

The insoluble binders are then removed via vacuum filtration.

The remaining solution is then acidified to pH1 with 10% Hydrochloric Acid to precipitate out the Acetylsalicylic Acid from solution.

This foamy solution is then vacuum filtered and washed with more dilute Hydrochloric Acid to obtain a more pure product.

This is then re-dissolved in the minimum amount possible of Potassium Carbonate solution, just so much that there are no unreacted reactants.

This solution is then combined with a previously prepared 0.01M solution of Copper Sulphate with stirring.

Bright blue crystals of Dicopper (II) Acetyloxybenzoate precipitate immediately.

These crystals are vacuum filtered. This is an extremely slow process.

LanthanumK - 1-6-2011 at 03:08

Did you make copper(I) oxide as well as copper(II) oxide?

There are also two different forms of copper(I) oxide, a red one and a yellow one.

[Edited on 1-6-2011 by LanthanumK]

#maverick# - 1-6-2011 at 04:46

fairly easy
copper sulfate + nahco3 solution
then dry the copper carbonate and heat till it decomposes to CuO

Trifluoroacetic - 1-6-2011 at 06:25

Thanks for sharing I will try this.

Quote: Originally posted by #maverick#

saw this on ozone's site seemed interesting might give it a try

Dicopper (II) Acetyloxybenzoate synthesis

16, 300mg Aspirin tablets are crushed.

The resultant powder is dissolved in 100ml of a 1M Potassium Carbonate solution to dissolve the Acetylsalicylic Acid.

The insoluble binders are then removed via vacuum filtration.

The remaining solution is then acidified to pH1 with 10% Hydrochloric Acid to precipitate out the Acetylsalicylic Acid from solution.

This foamy solution is then vacuum filtered and washed with more dilute Hydrochloric Acid to obtain a more pure product.

This is then re-dissolved in the minimum amount possible of Potassium Carbonate solution, just so much that there are no unreacted reactants.

This solution is then combined with a previously prepared 0.01M solution of Copper Sulphate with stirring.

Bright blue crystals of Dicopper (II) Acetyloxybenzoate precipitate immediately.

These crystals are vacuum filtered. This is an extremely slow process.

The WiZard is In - 1-6-2011 at 09:06

Hello all

I've been playing around with making various copper compounds and have photographed a few so far.

Ma Nature makes some nice copper compounds....

Dioptase tops my list.
http://en.wikipedia.org/wiki/Dioptase

Chrysocolla
http://en.wikipedia.org/wiki/Chrysocolla

Bornite
http://en.wikipedia.org/wiki/Bornite

Come upon my mind. Granted Ma has time on her side...
just set up an endowment to fund you experiments over
several thousands of generations.

Assuring that you were continual cloned would be a help.

----
Branch out to beryllium?!

Chapter 10. Artificial and Synthetic Beryls
John Sinkankas
Emerald and Other Beryls
Clinton Book Company 1981

djh
----
Extracted from :—
Harvey Mansfield
Sociology and Other 'Meathead' Majors
Archie Bunker was right to be skeptical of his son-in-law's opinions
Wall Street Journal 21V11

Science has knowledge of fact, and this makes it rigorous and
hard. The humanities have their facts bent or biased by values,
and this makes them lax and soft. This fact—or is it a value?—
gives confidence and reputation to scientists within the university.
Everyone respects them, and though science is modest because
there is always more to learn, scientists sometimes strut and often
make claims for extra resources. Some of the rest of us glumly
concede their superiority and try to sell our dubious wares in the
street, like gypsies. We are the humanists.

Others try to imitate the sciences and call themselves "social
scientists." The best imitators of scientists are the economists.
Among social scientists they rank highest in rigor, which means in
mathematics. They also rank highest in boastful pretension, and
you can lose more money listening to them than by trying to read
books in sociology. Just as Gender Studies taints the whole
university with its sexless fantasies, so economists infect their
neighbors with the imitation science they peddle. (Game theorists,
I'm talking about you.)

It's no wonder, then, that students make poor choices, avoiding
difficult courses, stumbling into easy ones, embracing counterfeit
majors. One might hope that with common sense they could learn
from experience, but according to the fact-value distinction,
experience cannot be shown to give one better judgment. There is
no "better" judgment. That's what colleges teach their students
these days.

Mr. Mansfield, a professor of government at Harvard, is also a
senior fellow of Stanford's Hoover Institution.

The WiZard is In - 1-6-2011 at 09:21

Hello all

I've been playing around with making various copper compounds and have photographed a few so far.

There dobe no doubt a SL of these in Mellors 16 volume (plus sps.)
opus, this ones name attracted my attention.

Copper nickelous dihydropentasulphate

A. Étard* obtained rose-coloured crystals of ... 2(CuSO4)-(NiSO4)-
H2SO4, by heating in a sealed tube at 200o, a soln. of the mixed
salts in the smallest possible proportion of water, and a large
excess of conc. sulpuric acid.

*Compt. Rend.,87. 602, 1878?

The WiZard is In - 1-6-2011 at 09:21

Hello all

I've been playing around with making various copper compounds and have photographed a few so far.

MrHomeScientist - 1-6-2011 at 10:50

I have also made CuCl2, CuCl, CuI, CuBr2, copper carbonate, hydroxide, and the oxide, I'm thinking about trying to make the trifluoroacetate salt also.

When you made the hydroxide, did you successfully get a nice dry sample? I've had a lot of trouble drying Cu(OH)2 without it decomposing into CuO or reacting with CO2 to make the carbonate. I start with a nice light blue voluminous, goopy precipitate but after washing and air drying it inevitably turns black or dark green. I've heard that cooling helps, and perhaps a dessicator bag is the way to go.

More related to your question, have you seen this compound from woelen's site? It's a really beautiful purple color and something I want to try myself, once I find some Na-DCCA.
http://woelen.homescience.net/science/chem/exps/raw_material...

The WiZard is In - 1-6-2011 at 11:26

Quote: Originally posted by MrHomeScientist

It do claimed you get copper hydroxide by reacting copper sulphate
with strong ammonia water. Don't know 'bout drying it though.

Another book sez. Copper(II) hydroxide is precipated by
treating a soluble copper(II) salt such as CuCl2 or CuSO4
with caustic soda or caustic potash.

Walks out to the living room and removes volume II or Brauer's
Handbook of Preparative Inorganic Chemistry from one of the three
bookcases Yup - complete details for copper(II) hydroxide on
pages 1013-14. Followed by Potassium cuprate(II) - a steel-blue to
deep blue crystalline powder.

I don't lend books and am not in the mood to scan this so....
you are going too have too go to the forums library and DL a
free copy.

Brauer should keep you busy to Christmas. Oh and while
you are doing the copper sulphate - ammonia water - sodium
hydroxide thing... you can make rayon.

http://tinyurl.com/3crfovu among a zillion other URL's.

djh
----
Wlat Street Journal
10 iv 2001
RINGSIDE LABOR: The bell hasn't rung on a
boxing union, supporters say.

The New York City-based Fighter's Institute
for Survival and Training, or Fist,
helps boxers with a life outside the ring.
But the group, founded by boxer Gerry
Cooney, also hopes someday to become
a union for boxers. Goals could include
minimum standards, as with actors, says
Joe Sano, Fist's president and an
official at an Office and Professional
Employees Internationals Union local. "The
whole idea is to crawl, walk, run," Mr.
Sano says.

That pace sounds familiar to Paul Johnson,
a Minneapolis ex-boxer. He has tried
to get the Boxers' Organizing committee
off the ground for about 12 years, but
plans to unveil the group before a televised
title fight never seem to come
together. Still, he believes a union is imminent.
"We've got the rocket ship on the pad,
we're pumping liquid nitrogen, and we're
going to blast off," he says.

[I hope they are not planning on a long trip! /djh/]

The WiZard is In - 1-6-2011 at 11:39

Found it - alcohol and all — it dobe in Brauer's Handbook of Preparative
Inorganic Chemistry, volume II page 1021.

You can DL a copy from the forums library among other sites.

djh
----
Dewey, Cheatham, and Screw
Investment Mavens
43 Park Row
New York, N.Y. 00001

CONFIDENTIAL PRIVATE OFFERING MEMORANDUM

Dear Client;

I have been looking around for a really good sound business deal that will not only be a
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Fortunately, I have found a real "sleeper" I though I would mention to you because
(although conservative) it looks like it will make a lot of money with very little invested
cash.

A friend of mine is opening a large cat ranch near Karmasillo, Mexico. It is our purpose
to start small; just one million cats. Cat skins can be sold for about 20 cents for the white
ones and up to 40 cents for the black. Each cat averages about 12 kittens a year; this will
give up about 12 million cat skins the first year, at an average of around 32 cents, making
our revenue about $3 million a year. This averages $10,000 a day excluding Sundays and
holidays.

A good Mexican cat person can skin about 50 cats a day. He or she gets $3.15 a day. It
will only take 663 people to operate the ranch, so the net profit will be more than $8200
per day.

The cats will be feed exclusively on rats. We will start a rat ranch adjacent to our cat
farm. Here is where the first year tax break really comes in. Because we will be utilizing
the rats to feed the cats, we can claim the expense of the entire first batch of rats
purchased during 1985. Rats multiply about times faster then cats do. If we start with a
million rats at a nickel each, we will have four rats per cat per day and a whopping
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Now here's the real innovation. The rats will be fed on the carcasses of the cats we skin.
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one cat.

Let me know as soon as possible if you are interested. Naturally, we want to keep this
deal limited to the fewest investors possible.

[Edited on 1-6-2011 by The WiZard is In]

Copper Phosphate?

Arthur Dent - 24-7-2011 at 09:43

An odd thing happened recently, I was trying to prepare a little bit of copper phosphate with a little ball of clean telephone wire (pure copper) and an aqueous solution of pure phosphoric acid (5%).

After pickling for a while in a jar, my resuls were somewhat surprzing. I obtained a perfectly clear, sky blue solution. Isn't copper phosphate supposed to be insoluble? Or is the remaining phosphoric acid keeping the phospate dissolved?

I was thinking I would have obtained at least a bit of a precipitate, but the stuff is perfectly dissolved, with not a trace of anything at the bottom...

The phosphoric acid MSDS says it is pure, and the telephone wire I have has been used often to succesfully synthetize the sulphate, the chloride and the basic carbonate...

Robert

Mr. Wizard - 25-7-2011 at 07:45

What happens if you neutralize the remaining acid with a little sodium bicarbonate? Later today, I'll try a little Phosphoric Acid on the Copper Phosphate I made and see if it dissolves in the acid. The only Phosphoric Acid I have is a concrete etching product that contains other ingredients.

#maverick# - 25-7-2011 at 08:12

An easier way to prepare copper phosphate is by reacting soln of cuso4 with a soln of Na3PO4 which can be bought at home depot

Mr. Wizard - 25-7-2011 at 16:01

@ Arthur Dent, I tried a little Concrete etchant which contains Phosphoric Acid on both Copper powder and my Copper Phosphate. The results surprised me. The Copper powder ( from an old CuSO4 + Vitamin C experiment), did produce a pale blue solution, but didn't react much with the Copper powder after heating with a candle for a few minutes. The Copper Phosphate however did dissolve much more than I thought it would. With warming it did produce a pale blue solution with a dilute Phosphoric Acid (Concrete Etch). It did not dissolve all the Copper Phosphate, however.

Copper Phosphate and Phosphoric Acid.jpg - 32kB

This shows the Copper Phosphate / Phosphoric Acid solution.

This may actually be useful, as my original use for the Copper Phosphate was to make artificial Turquoise by mixing with Aluminum Phosphate. Having some of the Copper in solution may make the formation easier.
[Edited on 26-7-2011 by Mr. Wizard]

[Edited on 26-7-2011 by Mr. Wizard]

Mr. Wizard - 25-7-2011 at 16:04

Due to my inexperience I can't seem to connect two photos to the post. Here is the powdered Copper with phosphoric Acid.

Copper powder and Phosphoric Acid.jpg - 33kB

Arthur Dent - 26-7-2011 at 03:10

@ Mr. Wizard: Thanks for confirming the solubility of Copper Phosphate in Phosphoric acid solution! So I guess that after a certain concentration, the mixture of Copper Phosphate in Phosphoric acid stops reacting with the metallic Copper just short of starting to precipitate the Phosphate. That's why my solution has been in a test tube for days and it's still clear and with not a trace of precipitate at the bottom, pretty much the same color as your first pic.

As you suggested, i'll try to drop a little bit of Sodium Bicarbonate in a sample of the solution to see what happens, but won't this just precipitate Copper basic Carbonate?

Robert

Mr. Wizard - 26-7-2011 at 12:22

@ Arthur Dent, yes adding Sodium Bicarbonate would eventually produce a basic Copper Carbonate, but I speculate that would only happen after most of the Phosphoric Acid had been converted to a Sodium Phosphate salt of some sort. While you added the Sodium Bicarbonate you could watch for fizzing and release of CO2. I may go out to the shop later and neutralize the sample to see what happens.

Looking at a 72nd Edition CRC Handbook of Chemistry and Physics, it shows copper (II) orthophosphate Cu3(PO4)2.3H2O as being soluble in H3PO4, acids, and NH4OH

The value for the Ksp= 1.39x10^-37 which makes it quite insoluble compared with many other 'insolubles'.

Edit to add that sodium bicarbonate did precipitate out what looked like the original copper phosphate . Since I didn't measure anything it's all rather 'iffy'.

[Edited on 26-7-2011 by Mr. Wizard]

OctanitroC - 16-1-2013 at 05:20

Has anyone managed to synthesize dry Copper (ii) Borate? I can only find spotty references about it on google. I've precipitated a slimy turquoise precipitate from borax and CuSO4 solutions, however I didn't try to filter it. Maybe I'll try that again. I've also dissolved CuCO3 in citric acid before to yield a sky blue solution, however the solution was too acid rich and excess citric acid goopified the solution when I tried to dry it. Has anyone isolated either of those two compounds?

EdMeese - 25-1-2013 at 15:17

My favorite is copper(I) acetate, on the 'nothing worthwhile is easy' line of reasoning. I tried the InorgSyn sublimation procedure with some scrap copper dust (not electrolytic powder as they say) and the yield was dismal, but I managed 15% after sublimation by reducing copper(ii) acetate in neat acetic acid with the same scrap copper. It's a beautiful white going to properly clear when the crystals are large enough ... pics! I must take pics!

Copper borate

bbartlog - 20-7-2013 at 11:57

Successfully made some of what is probably copper borate.

Experimental

200mmol of copper sulfate pentahydrate (50g) were dissolved in 250g of warm water.
400mmol of boric acid (25g) were dissolved in 250g of hot (80-90C) water.
380mmol of sodium bicarbonate (32g) were dissolved in 300g of warm water.

The first two solutions were combined by pouring the boric acid solution into the copper sulfate solution. No precipitate was seen even on close examination. This is more or less in line with expectation - I wouldn't expect to be able to prepare sulfuric acid by precipitating copper borate from a copper sulfate solution.
The solution was then transferred to a 1 liter mason jar, and gradually rendered more basic by piecemeal addition of the sodium bicarbonate solution, with the expected foaming as the carbon dioxide was expelled from solution. Slightly less than the stoichiometric amount of sodium bicarbonate was used so as to ensure that the resulting solution would still be somewhat acidic.
A pale blue precipitate settled to the bottom of the jar, similar in color to copper carbonate or copper phosphate.

This was set in a saucepan of boiling water and left to digest for an hour. After it settled overnight, the clear liquid supernate was decanted. The jar was filled with filtered water and the precipitate stirred (so as to dissolve any residual sodium sulfate). This was again left to settle overnight and then decanted, and this process was repeated once more.
The precipitate was transferred to a shallow glass pan and dried for three hours in an oven at 90C, then broken up and dried for another hour at this temperature.
The result was 33g of a relatively free-flowing blue powder. Note: this dust becomes airborne easily and is irritating when inhaled, even in small quantities.

Discussion

One uncertainty I had before performing this experiment was whether copper borate would actually precipitate before copper carbonate, given that both anions are available in this solution. One reason I heated the solution at near boiling for an hour following precipitation was to test for the presence of copper carbonate - under such conditions it would decompose to CuO and visibly darken the precipitate if it were present in any quantity. But no such darkening was seen.
The weight of the collected powder is consistent with a stoichiometry along the lines of CuB2H2O5 (CuB2O4.H2O). 200mmols of this compound would weigh slightly more than 33g. I believe that mechanical losses of copper (and by extension copper borate) were very small in this preparation. The decanted liquid was always clear (no visible quantities of Cu++) and no more than a few hundred milligrams of powder were lost during various transfers.

Further Work

I plan to see whether this compound will further dehydrate (to CuB2O4

on heating above 200C. I'll also be interested to see whether it, like boric acid, becomes more soluble in the presence of diols.

bfesser - 20-7-2013 at 12:01

Strange. That looks nothing like the copper borate I prepared many years ago. What you have appears to be <a href="http://en.wikipedia.org/wiki/Copper_carbonate" target="_blank">copper(II) carbonate</a> <img src="../scipics/_wiki.png" /> + <a href="http://en.wikipedia.org/wiki/Copper(II)_hydroxide" target="_blank">copper(II) hydroxide</a> <img src="../scipics/_wiki.png" />. Test it for <a href="http://en.wikipedia.org/wiki/Effervescence" target="_blank">effervescence</a> <img src="../scipics/_wiki.png" /> with dilute acid.

<a href="viewthread.php?tid=16452">Copper Borate?</a>

From an old laboratory notebook of mine, rife with error, terrible assumptions, and just plain awful note-taking:

Quote:

01.12.06

Copper (II) <del>Borate</del> Tetraborate — CuB4O7:

- 10ml CuSO4(aq) solution added to 50 ml beaker containing 10 ml Na2B4O7(aq) solution
- immediately formation of cloudy blue precip is observed
- phase sep observed with clear solution on top and blue solution below the precip
- added stir bar and put on mag. stirrer for a few minutes with 30 sec. reverse on
- while the reaction was on the stirrer, a few drops were pipetted off into a 10 x75mm test tube and a few drops of CH3COOH 1 M were adddd, then the tube was vortexed
- the precip dissolves with Acetic Acid – use it to clean glassware in experiment
-stored in labeled bottle to filter later

<del>Anhydrous MgSO4(s) + Acetic Acid</del>

- after the precip was allowed to settle for a while, the clear solution was blue, indicating an excess of CuSO4(aq), so some more Na2B4O7(aq

was added to the bottle
- I tried filtering the mix in a few ways, but nothing seemed to work very well, so I plan to 'borrow' some time on the lab centrifuges to separate this
- According to the notes on the "Cobalt Borates" experiment, gravity filtration after settling and decanting was used to successfully recover the CoB4O7(s) precipitate — it might be worth a try in this case, since CuB4O7(s) is very similar
- be sure to 'rinse' the precip with a few portions of distilled water to remove excess Na2B4O7(aq) and CuSO4 (aq

that would crystallize onto the precip when drying

Reaction Equation: 

Na2B4O7(aq) + CuSO4(aq) → CuB4O7(s) + Na2SO4(aq

Na2B4O7----------201.220g/mol
CuSO4-------------159.610g/mol
Na2SO4-----------142.044g/mol
CuB4O7-----------<del>1</del>218.786g/mol

- Gravity filtration works (using Whatman #1 )
- filter paper with wet precip transferred from funnel to 150mL Porcelain Evaporating dish and covered loosely with a paper towel to dry

If I were you, I would perform a test tube scale experiment where <a href="http://en.wikipedia.org/wiki/Borax" target="_blank">sodium tetraborate</a> <img src="../scipics/_wiki.png" /> is prepared first, then reacted with the <a href="http://en.wikipedia.org/wiki/Copper(II)_sulfate" target="_blank">copper(II) sulfate</a> <img src="../scipics/_wiki.png" /> solution. In my experience, copper(II) sulfate will react with <a href="http://en.wikipedia.org/wiki/Sodium_bicarbonate" target="_blank">sodium bicarbonate</a> <img src="../scipics/_wiki.png" />, precipitating copper(II) bicarbonate (rxn. I), which quickly decomposes (rxn. II) to copper(II) carbonate. It seems that the crude copper(II) carbonate can vary widely in color from a light blue (as you have) to an ugly green (I couldn't find my samples). It's likely that the composition of the crude product includes various hydrates, <a href="http://en.wikipedia.org/wiki/Copper(II)_oxide" target="_blank">copper(II) oxide</a> <img src="../scipics/_wiki.png" />, and perhaps even a little stabilized copper(II) bicarbonate.<ol type="I"><li>CuSO4(aq) + 2 NaHCO3(aq) → Cu(HCO3

2(s) + Na2SO4(aq)</li>
<li>Cu(HCO3

2(s) → CuCO3(s) + CO2(g) + H2O</li></ol>But after reviewing your procedure, I would expect any copper(II) carbonate/bicarbonate to react with the boric acid (depending on pH). I wouldn't be surprised if you had too much bicarbonate and accidentally precipitated the carbonate. But I could just be talking out of my arse…

Quote: Originally posted by blogfast25

Boric acid is an acid in name only, it is likely to be too weak to attack a water insoluble carbonate like CuCO3.
. . .
Likewise with the reaction between a neutral cupric salt and a borax solution: the high alkalinity of the borax solution is likely to precipitate either Cu(OH)2, a basic cupric salt or basic cupric borate. But it’s hard to tell which, without a solubility product (Ksp

for the target cupric borate.

[note] I searched, but couldn't seem to find my old copper precipitates. From what I remember, after drying the filter cake it formed a dark blue rock hard mass. I recall even having difficulty grinding it in the mortar to fit into a vial. Alas, the difference could just be the way I prepared and filtered my precipitate, I could have had Cu(OH)2 (possibly what you have, as well), or my memory could be faulty.

[Edited on 28.7.13 by bfesser]

bbartlog - 20-7-2013 at 12:46

It certainly *looks* like copper carbonate! But heating near boiling should have destroyed that compound. Nonetheless, your suggestion of an acid test is a good one.
It would not surprise me if some other copper borate looked rather different; I was trying to precipitate something containing two atoms of boron for every one of copper, but based on the information in the thread you link to above, there are compounds with other ratios, including three copper per two boron atoms. Which, if we regard boric acid as triprotic, might be better regarded as the 'true' copper borate, with my compound being copper metaborate hydrate...

Vargouille - 20-7-2013 at 17:09

I've tried to make the copper tetrahydroxyborate (Cu[B(OH)4]2) complex between boric acid and copper carbonate twice so far, and haven't succeeded yet. I mixed stoichiometric amounts of the two with enough water to dissolve the boric acid, and heated (boiled during the second trial) in the hopes of simultaneously prodding the boric acid into reacting and removing the resulting carbon dioxide. The first time, I stopped after a short time, and was left with a blue precipitate which bubbled upon addition of sulfuric acid. The second time, I got the same result, but I saved the remaining solution, and upon allowing it to evaporate, I received some amount of a white/clear crystalline substance which I took to be unreacted boric acid. Apparently copper tetraborate is quite simple to make, mind you.

bbartlog - 20-7-2013 at 20:15

Aside from the fact that no decomposition has been observed - which could just be because I haven't heated it enough - there's the issue that the powder weighs too much to be CuCO3. 200mmol of copper carbonate would only weigh 25g, and this powder weighs 33g. Anyway, I'll see tomorrow whether it effervesces on addition of HCl.

Your lab notes are neat, but unfortunately the first entry doesn't tell us the concentrations of the solutions being mixed - which leaves us in the dark as to what sort of stoichiometry we're looking at.

[Edited on 21-7-2013 by bbartlog]

bfesser - 20-7-2013 at 20:23

Those notes were crap. I just had nothing better to do than type them out. As for the weights, how dry is your product? Also, if it contained (a somehow stabilized) Cu(HCO3

2, this would help to account for the discrepancy in mass.

bbartlog - 21-7-2013 at 16:19

Tested as follows:

- took a spatula of the putative copper borate, put it in a test tube, and added 15ml of household vinegar. No effervescence was seen, but interestingly the solution did become colored blue, and on addition of another 15ml of vinegar all of the copper compound eventually dissolved.

Wasn't sure how dispositive this was, since acetic acid is pretty weak and will for example take quite some time to displace CO2 from calcium carbonate. So -

- took a somewhat larger quantity of the copper compound, a bit more than a gram, and put it in the bottom of a test tube. Added 10ml of 31% HCl. Immediately the liquid turned deep green, and a bit of foam was seen at the top. Note though that if we had 10mmol of CuCO3 (about what we would have given the rough estimate of weight), the gas volume produced would have to be over 200ml (and actually I would expect the solution to be ejected from the test tube). I'm guessing the foam is due to some small carbonate impurity, but it looks like it would have to be less than 1%.

After diluting the HCl with a similar quantity of water, I took a picture, which shows a precipitate at the bottom. This I would presume to be boric acid, freed from the copper. When I dumped the solution I could see that the precipitate was white, which consistent with that idea.

tl;dr Yes, it looks like it's copper borate.

H2libfront - 22-7-2013 at 01:40

I once made some 'copper tin green' which was used as a pigment in the old days. (I made it because I wanted to test it as exotic thermite, but that didn't really work unless I first decomposed it)

I think the formula is CuSnO3, copper stannate, and I made it by dropwise adding copper sulfate solution to a sodium stannate solution (made from SnCl2 solution with excess NaOH). The precipitate was brown when hydrated, but dried to a beautiful green.

[Edited on 22-7-2013 by H2libfront]

Copper antimonite

Bezaleel - 23-7-2013 at 03:47

Interesting. You can also make a copperantimonite, Cu(SbO2)2, by reacting freshly precipitated copperhydroxide with antimonytrioxide. You can tell the reaction by the colour change towards a very light green, lighter and more whitish than the green shown in H2libfront's picture above, but otherwise very similar in hue. If I remember well (but I would need to look that up), the reaction requires an alkaline environment to take place.

bfesser - 28-7-2013 at 07:37

Quote: Originally posted by bfesser

CuSO4(aq) + 2 NaHCO3(aq) → Cu(HCO3

2(s) + Na2CO3(aq)

I can't believe nobody spotted my error. Sodium carbonate; what? I guess nobody bothers to read my longer posts.

bbartlog - 28-7-2013 at 16:36

Oh, I read it. But it's easy to skim over a description like that when you already know what's being discussed.

Doktor Klawonn - 31-7-2013 at 16:08

Tetra amine copper (II) nitrate, [Cu(NH₃)₄](NO₃)₂

Lion850 - 6-12-2020 at 20:25

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.

artemov - 6-12-2020 at 23:51

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.

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

Lion850 - 7-12-2020 at 00:38

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!

artemov - 7-12-2020 at 00:48

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!

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

Lion850 - 7-12-2020 at 01:36

Have a look at this thread for info on the cyanurates:
http://www.sciencemadness.org/talk/viewthread.php?tid=155624

artemov - 7-12-2020 at 02:02

Quote: Originally posted by Lion850

Have a look at this thread for info on the cyanurates:
http://www.sciencemadness.org/talk/viewthread.php?tid=155624

Wow thanks. I especially love the color of the copper powder + cyanuric acid combi, and the well known NaDCC one

DraconicAcid - 7-12-2020 at 09:30

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).

Fery - 7-12-2020 at 13:05

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...

artemov - 7-12-2020 at 21:54

Tetramminecopper(II) is fairly stable- I've had samples for years that haven't lost any ammonia. It's not like hexamminenickel(II).

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...

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.

DraconicAcid - 7-12-2020 at 22:14

Quote:

Quote: Originally posted by artemov

Tetramminecopper(II) is fairly stable- I've had samples for years that haven't lost any ammonia. It's not like hexamminenickel(II).

Darn

You're disappointed that the colour stays nice?

artemov - 7-12-2020 at 22:32

You're disappointed that the colour stays nice?

No, cos I need a purple salt (in this case would be the hexaamminenickel)!

[Edited on 8-12-2020 by artemov]

DraconicAcid - 7-12-2020 at 23:26

Quote: Originally posted by artemov

You're disappointed that the colour stays nice?

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.

artemov - 8-12-2020 at 00:12

Thanks, but I have no access to en ...

Bezaleel - 8-12-2020 at 07:16

Vapour diffusion of isopropanol into an aqueous solution. Could you describe your setup? Feels like I have a learning moment ahead of me

MidLifeChemist - 8-12-2020 at 08:26

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.

DraconicAcid - 8-12-2020 at 13:07

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.

artemov - 9-12-2020 at 01:42

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

itsallgoodjames - 9-12-2020 at 08:22

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).

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?

DraconicAcid - 9-12-2020 at 23:37

I just checked a jar I made a decade ago. Still looks the same.

woelen - 9-12-2020 at 23:56

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).

artemov - 10-12-2020 at 02:35

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.

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]

Bezaleel - 10-12-2020 at 16:10

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.

Quote: Originally posted by artemov

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

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.

woelen - 11-12-2020 at 00:14

Hexaamminenickel(II) also can be kept indefinitely in a completely sealed vessel, but when not sealed properly, it quickly loses ammonia. Recently, I made a nickel-ethylenediamine-ammonia complex (dark blue), but after one day of exposure to air, quite a lot of pale blue powder was formed and it lost a lot of ammonia. I also made pure hexamminenickel(II) perchlorate, and that's the same. In a few days time, you see a change of color, if not stored perfectly sealed.

vano - 11-12-2020 at 09:31

tetraamminecopper(ii) nitrate

charley1957 - 11-12-2020 at 09:55

Vano that's a really pretty copper salt.

vano - 11-12-2020 at 10:37

Quote: Originally posted by charley1957

Vano that's a really pretty copper salt.

Thank you

[Edited on 11-12-2020 by vano.kavt]

itsallgoodjames - 11-12-2020 at 11:35

Tetraamminecopper(ii) nitrate is energetic, correct? That seems like a lot of explosive material to make at once, no?

vano - 11-12-2020 at 22:07

Quote: Originally posted by itsallgoodjames

Tetraamminecopper(ii) nitrate is energetic, correct? That seems like a lot of explosive material to make at once, no?

It isn't very energetic material like nickel hydrazine nitrate or perchlorate complexes. If you heat it will explode. But if you add a few grams of HMTD for every hundred grams then it will be quite explosive at room temperature.

[Edited on 12-12-2020 by vano.kavt]

TriiodideFrog - 12-12-2020 at 20:17

Just curious, what are you going to use the copper acetate for?

artemov - 13-12-2020 at 03:52

Quote: Originally posted by woelen

Hexaamminenickel(II) also can be kept indefinitely in a completely sealed vessel, but when not sealed properly, it quickly loses ammonia. Recently, I made a nickel-ethylenediamine-ammonia complex (dark blue), but after one day of exposure to air, quite a lot of pale blue powder was formed and it lost a lot of ammonia. I also made pure hexamminenickel(II) perchlorate, and that's the same. In a few days time, you see a change of color, if not stored perfectly sealed.

Cheers. I sort of sealed my tetraamminecopper, hopefully it will last.
Is this blue or purple? Would you say the hexamminenickel is more purple?

Lion850 - 25-12-2020 at 20:10

I tried to make copper gluconate C12H22CuO14 by double displacement reaction between calcium gluconate and copper sulphate. Calcium sulphate ppt out and after filtering the solution was first reduced in volume by slow boiling and then left out in a dish to dry.

After some 2 weeks a wet sticky blue-green substance was left. I tried to dry this in the sun a few days but it stayed sticky. It was then placed on a steam bath for some 4 hours but it is still a very sticky glob - color now dark olive green. See photo.

It does not seem hygroscopic. Any ideas how to get this to a dry powder state?

DraconicAcid - 25-12-2020 at 21:01

Triturate with alcohol?

Lion850 - 1-1-2021 at 02:03