Rust is commonly known as the reddish-brown flaky coating that forms on iron or steel when exposed to moisture and oxygen. The chemical name for rust is iron(III) oxide, and its chemical formula is Fe2O3.
Rust forms through a process called oxidation, where iron reacts with oxygen in the presence of water or moisture. This reaction can be represented by the following equation:
4Fe + 3O2 + 6H2O → 4Fe(OH)3
Over time, the iron(III) hydroxide formed in this reaction further dehydrates to form iron(III) oxide, which is the rust we see.
Rust is a sign of corrosion and can weaken the structural integrity of iron and steel objects. To prevent rust, protective coatings like paint or galvanization are often used.