What is the Color of Green Copper?

[ShawnD]

Pure copper metal is orange (or pink after being anodized), copper hydroxide is blue, copper oxide is black. So then why is the statue of liberty green?

 

[Pengwuino]

Supposedly its oxidation... and I've seen copper turn green though too..

 

[Math Is Hard]

I've seen lots of old pennies turn green. Must be the same thing.

 

[chroot]

I'm no chemist, but I believe there are several different oxidation states of copper, one of which is green.

- Warren

 

[so-crates]

Pure copper metal is orange (or pink after being anodized), copper hydroxide is blue, copper oxide is black. So then why is the statue of liberty green?

My guess was copper sulfate, but I looked it up and its probably more likely copper carbonate. As you may have learned in your intro chem classes(especially if your teacher was an environmental guy like mine) water reacts with carbon dioxide to form carbonic acid, which gives all rain its slight acidity. This carbonic acid will then react with the copper to form cupirc and cuprous carbonate.

 

[hypatia]

sulfates and acetates will turn it green.

 

[Borek]

http://en.wikipedia.org/wiki/Copper_carbonate