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Iron (Fe), element 26
Iron (Fe) is the chemical element with atomic number 26: a transition metal in group 8, period 4. At 25 °C it is a solid, with an atomic mass of 55.84 u.
Physical and chemical data
| Atomic number | 26 |
|---|---|
| Symbol | Fe |
| Atomic mass | 55.84 u |
| Density | 7.874 g/cm³ |
| Melting point | 1,537.85 °C (1,811 K) |
| Boiling point | 2,860.85 °C (3,134 K) |
| Electronegativity (Pauling) | 1.83 |
| Electron configuration | [Ar]4s2 3d6 |
| Atomic radius (van der Waals) | 194 pm |
| Oxidation states | +3, +2 |
| Physical state at 25 °C | solid |
| Family | transition metal |
| Group and period | 8 / 4 |
| Discoverer and year | known since antiquity |
Humanity has lived with iron since before chemistry existed as a science: there is no discoverer to record, only millennia of use.
Neighbours on the table
Horizontally, one proton less lands on Manganese (Z=25); one more lands on Cobalt (Z=27). Vertically, group 8 gathers relatives with similar behaviour: Ruthenium, Osmium, Hassium.
The story behind the name
The symbol Fe comes from the Latin ferrum, and the metal named an entire age of humanity. The little known detail is that the first iron our species used fell from the sky: before smelting was mastered, available iron came from meteorites, recognisable by its high nickel content; Tutankhamun's dagger, analysed in 2016, carries exactly that meteoritic signature. Today iron is the skeleton of the modern world and of you as well: the iron atoms in haemoglobin carry the oxygen in your blood, and its red colour comes from them.
Physical and chemical data: PubChem Periodic Table (NCBI, compiling NIST and IUPAC), public domain, snapshot of 2026-07-10. Temperatures converted from kelvin; historical notes cross checked against classic chemistry references.
Last updated: · Methodology and sources