Sciencemadness Discussion Board

Preparation of CuCl

Kola - 21-2-2012 at 07:44

I discovered,not too long ago that I can prepare a pretty reasonable amount of CuCl by electrolysis of NaCl using copper electrodes by using a low voltage of about 1.5 volts...low voltage means low rate but higher yield. This process is now the source of Copper(1) chloride in my lab. Both electrodes are made of Cu and the Cathode and the anode must be reasonably separated to prevent mixing of the CuCl formed at the anode with the Cu2O formed at the cathode. I was very surprised to see this occur and i think the Cu-Cl bond in copper(1)chloride is mainly covalent. Thinking This way, using a low voltage, the rate of Cl formation is low ensuring that a single atom of Cl reacts with an atom of Cu to form CuCl. CuCl is precipitated at the base of the cell. From my observations, A higher voltage favours formation of CuCl2 which eventually reacts with some OH- to form CuCl2...
Has anybody tried this? What were your observations?

Neil - 21-2-2012 at 08:06

Pssst starting multiply threads for one topic gets your hand held over a kettle of boiling H2SO3.

AirCowPeaCock - 21-2-2012 at 08:14

Quote: Originally posted by Neil  
Pssst starting multiply threads for one topic gets your hand held over a kettle of boiling H2SO3.


I believe you mean H2SO<b>4</b>. I <u>would</u> put my hand over boiling H2SO3!

Neil - 21-2-2012 at 08:18

:( fail. Yes, I had SO3 on the mind but H2SO4 was what I meant to type.


In ether case cross posting = bad.

LanthanumK - 21-2-2012 at 08:26

Yes. Some easily oxidized white CuCl is produced. It quickly turns green. A more expensive but quicker method of production was to reduce copper(II) chloride with pure Vitamin C crystals bought from a health food store. Pure white copper(I) chloride instantly precipitates in aqueous solution.

blogfast25 - 21-2-2012 at 10:55

Search this forum for CuCl: there are several interesting threads.

Kola - 21-2-2012 at 11:06

Quote: Originally posted by LanthanumK  
Yes.. A more expensive but quicker method of production was to reduce copper(II) chloride with pure Vitamin C crystals bought from a health food store. Pure white copper(I) chloride instantly precipitates in aqueous solution.

I'll try that but the Vitamin C i can get now is in tablets and not that soluble, good idea though. Maybe I'll just make the Vitamin C aqueous solution and filter off the undissolved stuff then I'll react with CuCl2.
Can CuCl be used for further synthesis? I'd like to know...also have u tried pouring a layer of Oil over the Electrolyte to reduce oxidation of CuCl? Try it...

ManBearSwine - 21-2-2012 at 20:56

I've found that the easiest way to make CuCl is to reduce aqueous CuCl2 with sodium sulfite (sold as chlorine neutralizer at pool stores). And, you could make some H2SO3 with it too!

woelen - 22-2-2012 at 01:37

Making CuCl is not that difficult, but isolating it and keeping it nice and white is surprisingly challenging. Wet CuCl is oxidized VERY easily by oxygen from the air, leading to formation of a hydrous oxychloride. If you have some nice white CuCl and expose this to air, then you see the change of color taking only seconds.

If you really want to make and isolate pure CuCl, then you MUST work in an oxygen-free environment and you have to meticulously prevent any contact with fresh air. Even commercial samples from chemical supply houses are green instead of white.

lysander - 18-9-2015 at 09:36

Quote: Originally posted by Kola  
I discovered,not too long ago that I can prepare a pretty reasonable amount of CuCl by electrolysis of NaCl using copper electrodes by using a low voltage of about 1.5 volts...low voltage means low rate but higher yield. This process is now the source of Copper(1) chloride in my lab. Both electrodes are made of Cu and the Cathode and the anode must be reasonably separated to prevent mixing of the CuCl formed at the anode with the Cu2O formed at the cathode. I was very surprised to see this occur and i think the Cu-Cl bond in copper(1)chloride is mainly covalent. Thinking This way, using a low voltage, the rate of Cl formation is low ensuring that a single atom of Cl reacts with an atom of Cu to form CuCl. CuCl is precipitated at the base of the cell. From my observations, A higher voltage favours formation of CuCl2 which eventually reacts with some OH- to form CuCl2...
Has anybody tried this? What were your observations?


This is a very cool idea, especially since it's such a pain to keep pure CuCl!

I'm trying it right now in a saturated NaCl solution. I just put the copper electrodes in separated at 1 inch and already see tiny bubbles on the anode (presumably from the free Na liberating H from the water).

Also getting what appears to be cuprite on the cathode.

Update: Probably not that easy. The sediment in the bottom is mostly brown; filters, spreading, and drying it only shows a hint of green. Meanwhile the water is acquiring a blue hue -- probably Cu(OH)2.

At the very least presumably the cathode has to be separated by a filter to prevent the Cu2O from dropping to the bottom and contaminating any CuCl that might get created.

I'd love to know how to get something like this to work though!

(Some related info here.)


[Edited on 19-9-2015 by lysander]