Why is copper chloride green?

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Marzy

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Why is copper chloride green?
« on: 13/01/2011 09:30:02 »
Marzy asked the Naked Scientists:
   
Why is copper chloride (CuCl2) green?

What do you think?
« Last Edit: 13/01/2011 09:30:02 by _system »

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Offline Bored chemist

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Offline chris

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Why is copper chloride green?
« Reply #2 on: 14/01/2011 08:17:33 »
Although it can be:

[attachment=13777]

This picture (from Wikipedia), shows a copper chloride solution prepared in the presence of (from left to right) increasing concentrations of chloride ions, which alters the chemistry and hence the colour of the solution.

Chris
I never forget a face, but in your case I'll make an exception - Groucho Marx

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Offline lightarrow

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Why is copper chloride green?
« Reply #3 on: 14/01/2011 11:12:55 »
Although it can be:

[attachment=13777]

This picture (from Wikipedia), shows a copper chloride solution prepared in the presence of (from left to right) increasing concentrations of chloride ions, which alters the chemistry and hence the colour of the solution.

Chris
I have not seen the picture in wiki, but according to what I remember, it should be the reverse: [Cu++(H2O)] should become green and then yellow-green in presence of higher conc. of Cl-.

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Offline Bill.D.Katt.

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Why is copper chloride green?
« Reply #4 on: 14/01/2011 14:56:16 »
I have not seen the picture in wiki, but according to what I remember, it should be the reverse: [Cu++(H2O)] should become green and then yellow-green in presence of higher conc. of Cl-.
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I agree, I have made quite a bit of copper chloride for coloring flames. If my H2O2 depletes before the HCl does, the solutions is yellower. Before the crystals have dried, they are green. I never try to dry them past the dihydrate form, which is a light blue.