I used white vinegar,hydrogen peroxide and some coins coated in copper and some copper wire. My solution started to have a blue color at the bottom but there were some white particles floating around. After 2 days my solution turned brown. No more blue. If accidentally some of the wires contained iron,could it be ferous acetate that gives this brown? My solution was all the time exposed to light,but I don't believe that this is the problem. I want to use the solution for shifting colors in natural dyeing.

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    $\begingroup$ Copper wires dipped in a $\ce{Cu^{2+}}$ solution produces a slow chemical reaction $\ce{Cu + Cu^{2+} -> 2 Cu^+}$. This cuprous ion $\ce{Cu^+}$ makes dark mixtures with cupric ions, according to Qualitative Analysis, by F. P. Treadwell, 1924. $\endgroup$
    – Maurice
    May 2, 2022 at 12:10

1 Answer 1


One source of your problem could be said coins. The coins are "coated in copper" but would have probably more reactive metals beneath, which reduce the copper back to metal as the base gets exposed to the solution. The displaced metallic copper, formed as fine particles in the solution, can then appear brown. If you used pennies where the base is zinc, that would give colorless ions when oxidized, so the only color you would see is that brown.

Copper wire is much more pure and so less prone to this side reaction. Using the wire alone as the copper source is more expensive, but recommended here.


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