Iron
Definition and meaning of Iron in chemistry.
![Iron element card: symbol Fe, atomic number 26, atomic mass 55.845, electron configuration [Ar] 3d⁶ 4s², oxidation states +3 +2, Transition metal, group 8, period 4, solid at room temperature.](/assets/images/terms/iron-chemical-element.webp)
Iron is a chemical element with the symbol Fe and atomic number 26. It is a common transition metal that forms much of the Earth's inner and outer core. By total mass, iron is the most abundant element found on our planet.
In more detail
Iron resides in group 8 of the periodic table of the elements. Scientists universally recognize this versatile metal for its strong ferromagnetic properties. These magnetic traits are fundamental to creating both permanent magnets and electromagnets.
Iron is a highly reactive transition metal that readily oxidizes in nature. When exposed to oxygen and moisture, the metal quickly forms hydrated iron oxides. People commonly refer to these flaky, reddish-brown oxide compounds as rust.
The solid metal exists in several different crystal structures known as allotropes. An allotrope is simply a different physical form of the same chemical element. Two common allotropes of iron include alpha iron and gamma iron.
Engineers rely on these specific crystal structures to control the physical properties of steel alloys. In chemical reactions, iron predominantly forms compounds in the +2 and +3 oxidation states. Chemists refer to the +2 state as ferrous and the +3 state as ferric.
The metal actively participates in a wide array of complex coordination and organometallic compounds. Biologically, iron is an absolutely indispensable element for almost all living organisms on Earth. It serves as the central atom in the heme group of human hemoglobin molecules.
Hemoglobin is the vital protein that transports oxygen through the blood of all vertebrates. Iron is also an essential structural component of cytochromes involved in cellular respiration processes.
Key facts
| Field | General Chemistry |
|---|---|
| Symbol | Fe |
| Atomic number | 26 |
| Atomic mass | 55.845 u |
| Category | Transition-Metal |
| State at room temperature | Solid |
| Melting point | 1538 °C |
| Boiling point | 2862 °C |
| Year discovered | Ancient times |
Iron serves as the primary base metal for manufacturing all types of steel. Construction companies universally use steel to build large buildings, bridges, and public infrastructure. They choose steel because it offers unparalleled structural integrity and long-lasting physical strength.
Frequently asked questions
Why does iron rust?
Iron rusts because it reacts directly with oxygen and water in the natural environment. This slow chemical reaction forms hydrated iron(III) oxide on the surface. This new oxide compound is a reddish-brown, flaky substance that weakens the metal.
How is iron transported in the human body?
Iron travels safely through the blood plasma by binding to a specialized glycoprotein called transferrin. The transferrin protein delivers the iron atoms directly to living cells. The cells then use it to synthesize hemoglobin and other essential biological proteins.
Related terms
Sources & references
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