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NEMO-Chemistry
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[*] posted on 27-11-2017 at 17:58
Cobalt compounds


I have done a few copper compounds now, including basic carbonate, and asprinate (sorry to those that hate the name). I want to now do some Colbalt ones starting point is Colbalt chloride.

Can Colbalt form Colbat asprinate? i cant find much on it. I am aware the risks with Colbalt compounds, my scale is small and just enough to fill a 25ml vial for display.
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[*] posted on 27-11-2017 at 19:42


I don't think cobalt forms an aspirinate, but you can make potassium tricarbonatocobaltate(III) which is cool.



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[*] posted on 27-11-2017 at 22:10


If you need ideas you can check this site
http://onyxmet.com/?route=product/category&path=69_93_27...




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[*] posted on 27-11-2017 at 22:43


Ooooh. Pretty.



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[*] posted on 28-11-2017 at 02:50


Quote: Originally posted by DraconicAcid  
I don't think cobalt forms an aspirinate, but you can make potassium tricarbonatocobaltate(III) which is cool.

I prefer to make things i can pronounce easily lol, dosnt exactly trip off the tongue does it!! Nasty colour for a colbalt salt!

Thx for the link VV.

Slowly getting my pointless but colorful compound collection done.
I got 100 nice tubes with screw lids from China last week, only to trip over the step carrying them to the lab :(.

Might just be me being tight, but those tubes are costing more by the day!

WOW i could spend a fortune on that site!! Colbalt has some amazing colours.

[Edited on 28-11-2017 by NEMO-Chemistry]
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[*] posted on 28-11-2017 at 09:56


Quote: Originally posted by NEMO-Chemistry  
Nasty colour for a colbalt salt!
.... Colbalt has some amazing colours.


COBALT only has one L.

And it might not be a nice colour (I think it's a nice, very dark green), but it is a useful starting material for cobalt(III) complexes.

[Edited on 28-11-2017 by DraconicAcid]




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[*] posted on 28-11-2017 at 19:13


Quote: Originally posted by DraconicAcid  
Quote: Originally posted by NEMO-Chemistry  
Nasty colour for a colbalt salt!
.... Colbalt has some amazing colours.


COBALT only has one L.

And it might not be a nice colour (I think it's a nice, very dark green), but it is a useful starting material for cobalt(III) complexes.

[Edited on 28-11-2017 by DraconicAcid]

My spelling is getting worse!

The salt i looked up was yellow ish, a nasty yellow ish. I better check i was looking at the right one. My new glasses will be here Friday :D.

Its the Blue colours i am mainly after, then the purples and pinks. None of this will make ANY sense until i complete the collection, but there is a method behind this madness.
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[*] posted on 28-11-2017 at 19:16


Blue- tetrachlorocobaltate(II) ion. You probably want a large cation, such as choline or tetraalkylammonium.



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[*] posted on 28-11-2017 at 19:31


Quote: Originally posted by DraconicAcid  
Blue- tetrachlorocobaltate(II) ion. You probably want a large cation, such as choline or tetraalkylammonium.

Thanks alot, that has saved me alot of hunting around!.

I havnt worked with any COBALT salts before. They are a bit exotic price wise for me :D.

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[*] posted on 28-11-2017 at 20:01


Also Thenard's blue- dissolve aluminum in sodium or potassium hydroxide, and add a solution of cobalt salt. It's not a nice crystally precipitate, but it's blue.



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[*] posted on 28-11-2017 at 20:46


Cobalt forms an acetoacetonate complex which catalyzes the hydration of alkenes. Acetoacetone is not a household chemical but it's cheap.

There's also the hexamminecobalt (III) ion which curiously precipitates as the bromide (this being the only insoluble bromide that isn't a heavy metal)




[Edited on 04-20-1969 by clearly_not_atara]
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[*] posted on 3-12-2017 at 11:43


Quote: Originally posted by NEMO-Chemistry  
Quote: Originally posted by DraconicAcid  
Blue- tetrachlorocobaltate(II) ion. You probably want a large cation, such as choline or tetraalkylammonium.

Thanks alot, that has saved me alot of hunting around!.

I havnt worked with any COBALT salts before. They are a bit exotic price wise for me :D.



One can get CoCO3 here by the pound for a fairly good price. I also suggest that you try making Co Oxalate. It's a similar procedure to Ni or Fe Oxalate, and produces a nice salmon precipitate which, when decomposed, acts like the Ni and Fe salts.

Another good experiment is making the hydrates of CoCl2!
You start out by neutralizing as much HCl with CoCO3 as you can, until you end up with a saturated solution. Some CoCl2 * 6H2O may crystallize if the solution is cooled even a bit. CoCl2 * 6H2O is a deep burgundy crystalline solid, and rather deliquescent. Heat this to obtain the purple dihydrate, or you can go all the way to the anhydrous, which is a light blue color. I did all three, and have a nice little collection. I also have Co Sulfate & Hypophosphite, both of which are a beautiful cherry color. Cobalt Silicate is very nice too, making a rich purple precipitate when a soluble silicate is added to a Co salt solution. When dried, it lightens up a bit. You can also make α-Co(OH)2, which is a nice, bluish turquoise color by addition of ammonia to a Co salt solution, followed quickly by dilution with water. You can then precipitate it and store it. Picture below of α-Co Hydroxide. vvv

24337475_1283687325111283_1083497188_n.jpg - 40kB




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[*] posted on 3-12-2017 at 15:05


Quote: Originally posted by Tetra  
Quote: Originally posted by NEMO-Chemistry  
Quote: Originally posted by DraconicAcid  
Blue- tetrachlorocobaltate(II) ion. You probably want a large cation, such as choline or tetraalkylammonium.

Thanks alot, that has saved me alot of hunting around!.

I havnt worked with any COBALT salts before. They are a bit exotic price wise for me :D.



One can get CoCO3 here by the pound for a fairly good price. I also suggest that you try making Co Oxalate. It's a similar procedure to Ni or Fe Oxalate, and produces a nice salmon precipitate which, when decomposed, acts like the Ni and Fe salts.

Another good experiment is making the hydrates of CoCl2!
You start out by neutralizing as much HCl with CoCO3 as you can, until you end up with a saturated solution. Some CoCl2 * 6H2O may crystallize if the solution is cooled even a bit. CoCl2 * 6H2O is a deep burgundy crystalline solid, and rather deliquescent. Heat this to obtain the purple dihydrate, or you can go all the way to the anhydrous, which is a light blue color. I did all three, and have a nice little collection. I also have Co Sulfate & Hypophosphite, both of which are a beautiful cherry color. Cobalt Silicate is very nice too, making a rich purple precipitate when a soluble silicate is added to a Co salt solution. When dried, it lightens up a bit. You can also make α-Co(OH)2, which is a nice, bluish turquoise color by addition of ammonia to a Co salt solution, followed quickly by dilution with water. You can then precipitate it and store it. Picture below of α-Co Hydroxide. vvv



thx for the info, i have ordered both the chloride and carbonate. unless i am missing a super cheap pottery supplier in the UK, pottery suppliers seems to cost more than other sources and for less pure products.
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[*] posted on 4-12-2017 at 08:38


I've messed about with a few cobalt compounds in the past. Here are a couple of pictures of cobalt complexes.

Cobalt (III) complexes.jpg - 231kB Cobalt Thiocyanate.jpg - 474kB

and of course then there is cobalt(III)en perchlorate (en=ethylene diamine).

Cobalt(III)EN perchlorate.jpg - 181kB

Which goes -

Attachment: My Movie.mp4 (3.9MB)
This file has been downloaded 423 times




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[*] posted on 4-12-2017 at 09:29


Wow, the carbonate looks very interesting. A green complex of cobalt? I never have seen such a thing.

How did you make the green carbonato-complex? That definitely is something I would like to reproduce.

---------------------------------------------

The [Co(en)3](ClO4)3 indeed is fun stuff. I made that myself, together with a nickel complex (purple), a copper complex (dark blue), a zinc complex (white) and a cadmium complex (white).




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[*] posted on 4-12-2017 at 19:28


Speaking of nickle.. I cant find the post where someone mentioned a coin made from it. I think it was a polish coin but cant remember. Looking online nickel is really expensive. Actually most things have shot up in price!

Last year I got 25KG Potassium Chloride from a garden supplier. the cost was £29 delivered. I looked last night to get some more, same stuff from same place is now £62

I dont buy many in large amounts, but those that i so have really gone up in price, copper sulphate in 10kg size is pretty expensive... Anyway anyone know which coin was mainly nickel?

I am waiting for my cobalt to arrive, having overspent on equipment i need to try and save on chems :D
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[*] posted on 4-12-2017 at 20:18


Quote: Originally posted by woelen  

How did you make the green carbonato-complex? That definitely is something I would like to reproduce.

DOI: 10.1021/ja01504a004

Cobalt chloride, sodium carbonate, and hydrogen peroxide.




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[*] posted on 5-12-2017 at 07:56


Quote: Originally posted by DraconicAcid  
Quote: Originally posted by woelen  

How did you make the green carbonato-complex? That definitely is something I would like to reproduce.

DOI: 10.1021/ja01504a004

Cobalt chloride, sodium carbonate, and hydrogen peroxide.


Amounts? Process? Order of addition?




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[*] posted on 5-12-2017 at 09:11


Quote: Originally posted by Tetra  
Quote: Originally posted by DraconicAcid  
Quote: Originally posted by woelen  

How did you make the green carbonato-complex? That definitely is something I would like to reproduce.

DOI: 10.1021/ja01504a004

Cobalt chloride, sodium carbonate, and hydrogen peroxide.


Amounts? Process? Order of addition?


Check the referenced paper for an experimental...
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[*] posted on 5-12-2017 at 10:54


Anyone interested in purchasing any cobalt acetate to make other cobalt compounds? I have 5lbs of excess cobalt acetate on hand to sell or to do exchange with. 1lb of cobalt acetate is 15.00 plus shipping if anyone is interested.
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[*] posted on 8-9-2020 at 00:14


I accidently seem to have made a cobalt compound that gives a lovely dark green solution with concentrated HCl - but what is it?

The idea was to see if cobalt iodate could be made by doing a double displacement reaction between solutions of sodium iodate and cobalt acetate. This failed as far as I can see but I ended up with something interesting: a light grey powder that gives a lovely green solution with concentrated hydrochloric acid. How this happened:
- 10g NaIO3 dissolved in 100ml hot water. This NaIO3 was some 9 months old (in a clear jar) and a slightly brown, so there was probably some free iodine. It dissolved quite easy and gave a very pale brown solution.
- 6.4g (CH3COO)2Co.4H2O was dissolved in 30ml water, giving a red solution
- The cobalt acetate was slowly poured into the sodium iodate while stirring
- A maroon-purple suspension formed.
- The solution was then brought to boil while stirring. The reason I did this was to try and get a anhydrous cobalt iodate to ppt out; it is said to have low solubility at 100C.
- Close to boiling the color became more brown and it started to offgas lots of I2! See photo below.
1 Reaction proceding.jpg - 697kB

- I initially thought this may be free I2 from the NaIO3 and continued to keep it boiling. After some 10 minutes the color of the solution was a bit lighter brown but there was no sign of the I2 coming off reducing.
- There was visible suspension, so I switched off the heat and let the solution cool down slowly, and then stopped the stirring. This have a brown solution with a dark layer on top (looking like I2 in water) and a heavy grey-pale blue ppt - I say heavy because it settled out quickly.
- The supernatant solution was decanted, and the ppt washed with ethanol to dissolve remaining I2. It was then gravity filtered. In the filter, the remainder, a dark grey powder, was twice washed with acetone by which time the acetone ran through clear. See photo of the dark grey remainder below.
2 Dark grey filtrate.jpg - 442kB

- The filter paper with the remainder was put aside to be dried in the sun the next day.

I started to clean up. The reaction beaker had a difficult to remove layer of the grey ppt on the bottom. I added a bit of concentrated HCl to see if that would dissolve it...expecting the usual blue solution of anhydrous CoCl2. The grey layer dissolved in an instant...but gave a lovely green solution! See photo.
3 HCl added to beaker to clean.jpg - 388kB

I started to look online mainly on Atomistry and Wikipedia to try to understand how cobalt wth HCl can give a green solution. What I did learn was that Cobalt makes many complex oxides, and in some circumstances iodine play a part in this. The oxides / oxide hydrates can have many colors, including grey.

The next day the power had lightened in color and after trying for some hours in the sun under a steel dish it appeared bone dry and light grey with just a hint of blue to the naked eye. See photo. Recovery was 3.4g
4 Dry light grey powder.jpg - 483kB

I tested the dry light grey powder with concentrated HCl, and again got a deep green solution. This time I stoppered the test tube with the green solution and put it aside to see if it remains green over time.
5 Powder with conc HCl.jpg - 466kB

What is the grey powder that gives a green solution with HCl, and what is the solution? Did I accidentally make a complex?


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[*] posted on 8-9-2020 at 04:30


Lion850: Blue Co solution in conc. HCl isn't anhydrous CoCl2 but [CoCl4]2-.

Co2+ + 4Cl- <--> [CoCl4]2-

IO3- + 6HCl - - > [ICl4]- + Cl2 + 3H2O

[CoCl4]2- is blue, [ICl4]- is yellow. Blue + yellow = green.

Nemo-chemistry: Co phosphates have interesting colours. Cobalt phosphate is violet, ammonium cobalt phosphate is purple and cobalt pyrophosphate is pink. If you don't have pyrophosphate, you can make by careful dehydration of Na or K hydrogenphosphate.

I made some hydrated CoMoO4 which have beautiful violet colour. I read that anhydrous should be green but I never try to prepare it. I also made ammonium hexamolybdatocobaltate(II). I synthesed pink and red hexamolybdatocobaltate - first by precipitation, second by crystallization. I don't know if difference in colour is caused by particle size or composition. I will post article about their synthesis on my website. Btw. - also exist brown hexamolybdatocobaltate(III).

Cobalt tungstate is pink. I think that tungstate will also form similar complex anion with cobalt as molybdate, but I don't check it yet.

CoBr2.6H2O is red, anhydrous CoBr2 is green.

I read about green trisoxalatocobaltate(III).

You can also find lot of procedures about making [Co(NH3)6]Cl and [Co(NH3)5Cl]Cl2.

You can make some X2Co(SO4)2.6H2O crystals where X = K or NH4. You can also mix this solution with some Ni or Cu sulfate to get mixed crystals.

I read on SM about blue cobalt aluminate which can be make by mixing Co(II) salt with sodium aluminate solution.




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[*] posted on 8-9-2020 at 14:49


Hi Bedlasky thank you so many colourful cobalt compounds to try.

I hope someone can advise on the grey powder I made that gives the green with HCl. I’m gonna try to make more of this powder in slightly different ways to try and understand better.
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[*] posted on 8-9-2020 at 16:03


Lion850: Grey compound must definitely contain iodate and cobalt, because of reactions which I wrote in my first post.

Here is something about CoIO3:

http://cobalt.atomistry.com/cobalt_iodate.html

[Edited on 9-9-2020 by Bedlasky]




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[*] posted on 8-9-2020 at 16:06


Quote: Originally posted by Bedlasky  
Lion850: Blue Co solution in conc. HCl isn't anhydrous CoCl2 but [CoCl4]2-.


I believe that's a matter of some debate. The blue colour is certainly due to a tetrahedral cobalt(II) complex, but depending on pH and chloride concentration, it may be [Co(H2O)2Cl2], [Co(H2O)Cl3]- or [CoCl4]=.




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