Whenever using copper as anode, I end up with cyan dust that doesn't dissolve in water.

mysterious copper oxide

What's that (presumably) oxide? Is it poisonous? Can I dissolve it in something to perform electroplating with it?


1 Answer 1


It appears to be copper hydroxide or copper carbonate. Copper oxide tends to be black/grey/brown. Copper hydroxide is blue and copper carbonate is green. Copper carbonate forms when the hydroxide is exposed to CO2.

If you would like to dissolve it, try an acidic solution.

  • $\begingroup$ I would like to dissolve it in order to perform electroplating with it. Would it work? $\endgroup$ Commented Jun 27, 2014 at 9:40
  • $\begingroup$ I find that copper chloride solutions tend to be the most reactive. If I were you I'd try dissolving it in HCl. It will dissolve in acid and should work for electroplating. $\endgroup$ Commented Jul 8, 2014 at 19:20
  • $\begingroup$ I have dissolved it in sulphuric acid since hydrochloric was harder to obtain at the moment. The copper won't stick to most surfaces however. It just forms dust around them. $\endgroup$ Commented Sep 12, 2014 at 0:36
  • $\begingroup$ It should stick to a metallic surface. Insure that the metal surface is free of corrosion by pickling. $\endgroup$ Commented Sep 12, 2014 at 2:49

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