Iron

Atomic number

26

Atomic mass (u)

55.84

Category

Transition metal

Standard state

Solid

Melting point

1537.85 °C (1811 K)

Boiling point

2860.85 °C (3134 K)

Density (g/cm³)

7.874

Electronegativity (Pauling)

1.83

Electron configuration

[Ar]4s2 3d6

Oxidation states

+3, +2

Atomic radius (pm)

194

First ionization energy (eV)

7.902

Discovery & recognition

Discovery year / period (PubChem)

Ancient

Discovery credited to (RSC)

No individual discoverer recorded by this source

Date or period recorded by RSC

approx 3500BC

Discovery place

Known since antiquity; no single first-discovery place is established.

An ancient date does not identify a first human discovery. Different references may date observation, isolation and formal recognition differently.

Natural occurrence & production

The creation of an element’s nuclei and its concentration into terrestrial deposits are different processes. The occurrence note below concerns its presence or production on Earth; it is not a complete account of nucleosynthesis.

“Iron is the fourth most abundant element, by mass, in the Earth’s crust.”

Royal Society of Chemistry · occurrence excerpt ↗

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Reference values are not product specifications. Blank values have not been estimated. For superheavy elements, some properties and family assignments are theoretical or incompletely measured.