鐵銹 是否等於 Fe2 O3?

Yes.

During rusting, iron metals will lose electrons.

Then iron ions(Fe 2+) then will react with oxygen in air to form iron oxide.(Fe2 O3)

Then iron oxide will then hydrodated by water to form iron oxide* n water.
(Fe2 O3*n*H2O)

2007-04-29 22:08:16 補充：
赤鐵礦is Fe2O3But since 赤鐵礦 is raw minerals ,there is many impurities.

正確泥講 唔係 Fe2O3
而係
Fe2O3．ｘH2O
因為鐵生銹要水...
所以唔係Fe2O3