Copper Oxide

Most recent answer: 10/22/2007

Q:
Thank you very much for answering my question I have found very good results and I was wondering (Please answer fast because due tomorrow =]) why do bronze, brass, and copper rust with a green powder? I know why iron and other elements like aluminum get there types of rust, but your the only people that I can look towards to answer...
- Kyle (age 13)
Shorecliffs Middle School, San Clemente, Ca.
A:
Copper oxide is green. There’s copper in bronze and brass, also.

Mike W.

(published on 10/22/2007)

Follow-Up #1: whoops- we stand corrected

Q:
Your answer is incorrect, Copper Oxide is generally thought of as black copper oxide or Cupric Oxide, another form is Red Copper Oxide or Cuprous Oxide.

The geeen you see on statues or other is formed when copper reacts with CO2 that has dissolved in Water to make carbonic acid, this weak dilute acid reacts with the copper to form a carbonate and the green patina you see.
- Skip Klatt (age 45)
Long Grove IL
A:
Skip- Thanks for straightening that out. It seemed like a good idea to leave in my wrong answer and your correction, to encourage more corrections.  Mike W.

(published on 10/22/2007)