• Question: if mattalic salts are present in the hair and other products are added why does the hair go green?

    Asked by benbilly to James, Marcus, Martin, Rob, Suzanne on 20 Mar 2012.
    • Photo: Robert Thompson

      Robert Thompson answered on 20 Mar 2012:

      I’m sorry Benbilly, I have no idea. This really isn’t me field of science. But thanks for telling me about it. I know how to avoid green hair now.

    • Photo: Marcus Gallagher-Jones

      Marcus Gallagher-Jones answered on 21 Mar 2012:

      Hi benbilly i can answer that one. As you correctly pointed out it is due to metal salts in particular Copper salts. What is happening is that copper (ii) ions present in water are being oxidised by reacting with Hydroxide ions in whatever products you are using. This oxidises them to Copper Hydroxide (Cu(OH2)) which has a green colour. It can occur if the products you are using are fairly basic, or if the water’s PH balance is off. It also occurs over time on the surface of copper in air, which is why some statues turn green.