1. Iron(II) oxide (FeO):
* This formula represents iron in the +2 oxidation state, also known as ferrous oxide.
* It is a black, solid compound and is relatively unstable in air.
2. Iron(III) oxide (Fe₂O₃):
* This formula represents iron in the +3 oxidation state, also known as ferric oxide.
* It is a reddish-brown, solid compound and is much more stable than FeO. It is the main component of rust.
There is also another common iron oxide, magnetite (Fe₃O₄):
* This formula represents a mixed oxidation state of iron, with both +2 and +3 oxidation states present.
* It is a black, ferromagnetic compound and is responsible for Earth's magnetic field.
Therefore, the correct chemical formula for iron oxide is not a single answer, but depends on the specific oxidation state of iron.
