* Compound: A compound is formed when two or more elements chemically combine in a fixed ratio. The resulting substance has properties different from the original elements.

* Mixture: A mixture is a combination of two or more substances where each substance retains its own properties. The components can be separated by physical means.

Iron oxide (FeO) is formed when iron (Fe) reacts chemically with oxygen (O). The resulting compound has a different chemical formula and properties than either iron or oxygen alone.

Examples of Iron Oxides:

* Rust (Fe₂O₃): This is a common form of iron oxide, known for its reddish-brown color.

* Magnetite (Fe₃O₄): This is a magnetic form of iron oxide.

Since iron oxide is formed by a chemical reaction and has a fixed ratio of iron and oxygen atoms, it is a compound.