The Statue of Liberty is a landmark that every American recognizes. The Statue of Liberty is easily recognized by its height, stance and distinctive blue-green color when this statue was first delivered from France, Its appearance was not green. It is brown, its copper "skin" color. So how did the Statue of Liberty come about? Change colors? A change in appearance is a direct result of corrosion. The primary is copper part of the statue slowly oxidized from the air. Oxidation-reduction reactions of copper metal occur in several stages in the atmosphere. Copper metal oxidizes to copper (I) oxide (Cu2O). Red, then copper(II) oxide, which is black

2Cu(s) + 12O2(g) ⟶ Cu2 O(s) (red)

Cu2 O(s) + 12O2(g) ⟶ 2CuO(s) (black)

Coal, often high in sulphur, was burned extensively in the early part of the last century. As a result, Sulfur trioxide, carbon dioxide and water all react with CuO

2CuO(s) + CO2(g) + H2 O(l) ⟶ Cu2 CO3 (OH)2(s) (green)

3CuO(s) + 2CO2(g) + H2 O(l) ⟶ Cu2 (CO3)2 (OH)2(s) (blue)

4CuO(s) + SO3(g) + 3H2 O(l) ⟶ Cu4 SO4 (OH)6(s) (green)