26FeIron55.8452[Ar] 3d⁶ 4s²
transition metal
Iron
Iron is a chemical element with symbol Fe (from Latin:ferrum) and atomic number 26. It is a metal in the first transition series. It is by mass the most common element on Earth, forming much of Earth's outer and inner core.
A stylized shell model. Electrons are quantum objects, not particles following these literal paths. Sizes and motion are illustrative.
Electrons by shell
Electron configuration
3d6
4s2
18 is the [Ar] core total across three shells.
At a glance
- Atomic number
- 26
- Atomic mass
- 55.8452 u
- Phase
- Solid
- Density
- 7.874 g/cm³
- Melting point
- 1,811 K
- Boiling point
- 3,134 K
- First ionization energy
- 762.5 kJ/mol
- Electronegativity
- 1.83
- Electron affinity
- 14.785 kJ/mol
- Molar heat capacity
- 25.1 J/(mol·K)
- Period
- 4
- Appearance
- lustrous metallic with a grayish tinge
Conditions and isotopes affect measured properties. Some properties of short-lived elements are predicted. Electronegativity uses the Pauling scale.
Keep exploring
Explore the stories, imagery, and reference data in more depth. Properties with no value in the reference are marked unavailable.