Iron (Fe), a chemical element and metal, is the most commonly used and cheapest metal. Its chemical composition is primarily defined by its isotopes and can vary depending on the source and processing.
Isotopic Composition
Naturally occurring iron is a mixture of four stable isotopes:
- Iron-56 (⁵⁶Fe): 91.66%
- Iron-54 (⁵⁴Fe): 5.82%
- Iron-57 (⁵⁷Fe): 2.19%
- Iron-58 (⁵⁸Fe): 0.33%
These percentages represent the relative abundance of each isotope in naturally occurring iron.
Other Elements in Iron Samples
While pure iron consists solely of these isotopes, samples of iron often contain trace amounts of other elements. The exact composition will depend on the source of the iron (e.g., meteorites, ores, manufactured iron). Examples include:
- Nickel (Ni): Often found in significant amounts in iron meteorites (5-10%).
- Cobalt (Co): Present in trace amounts in iron meteorites.
- Manganese (Mn), Phosphorus (P), Sulfur (S): Present in varying amounts in different iron products, with levels depending on the refining process. For example, ARMCO Pure Iron has specified maximum limits for these elements.
Compounds of Iron
Iron readily forms various compounds with other elements. Examples include:
- Oxides: Hematite (Fe₂O₃) and Magnetite (Fe₃O₄) are common iron oxides found in nature.
- Sulfates: Ferrous sulfate is a commonly known iron sulfate compound.
- Chlorides: Ferric chloride is another example of an iron compound.
- Organometallic Compounds: Ferrocene is a well-known organometallic compound containing iron.
The specific compounds formed depend on the chemical environment and the reacting elements. Redox conditions, in particular, significantly influence the chemical forms of iron present. For example, the presence of reactive organic molecules can influence how iron is associated with other substances.
