Steel is an example of a solid solution, a category of chemical mixes in which two or more solid-state molecules unite to create a single entity while keeping their distinct identities. Steel is made of metals that are not chemically connected to one another.

Steel is an alloy mostly made of iron with a small amount of carbon. Many steels combine iron and steel with additional metals to give the final product certain qualities like strength, heat resistance, or flexibility. Because iron doesn’t chemically connect with the carbon and other ingredients, steel is regarded as a mixture rather than a compound. In contrast, the carbon atoms in basic iron-carbon alloys are tiny enough to occupy the voids in the iron crystal. The nickel atoms in steel alloys that contain heavier elements like nickel take some of the place of the iron atoms in the crystal structure.