How to treat iron oxide, or rust?Please supply chemical formula.

Rust is the generic name for iron oxide, Fe2O3
(subscripts).  Iron, in the presence of oxygen, using water as a catalyst, will form
rust.  Rust is the corrosion of iron.  It typically occurs at surfaces exposed to the
elements, where oxygen and water are readily available.  Depending on the availability
of of oxygen and water, it makes use of two chemical
formulas:

(Fe2+)  + 2(H2O) ---> Fe(OH)2  +
2H+

(Fe3+)  + 3(H2O) ---> Fe(OH)3  +
3H+

Rust can have a red physical color, although in marine
environments, in the absence of oxygen, a green color is manufactured.  It should be
noted rust does not insure any protection to underlying layers of
iron.

To protect iron from rusting, protective layers of
coatings must be applied.  Stainless steel, or chromium (III) oxide, provides such a
coating.  The process of galvanization, which coats the iron with a protective layer of
zinc, is another process which slows the corrosive process.  In harsher, more corrosive,
marine environments, cadmium is a more suitable protective
coating.