Iron (Fe)
Element 26 · Transition metal · Solid at 25 °C · Group 8, Period 4
Iron is the most-used metal on Earth and the main ingredient of steel. It forms most of our planet's core, and in hemoglobin it carries the oxygen in your blood.
On the periodic table, iron sits in group 8 in period 4. It is one of 38 elements classified as a transition metal, and at room temperature (25 °C) it is a solid.
Transition metals occupy the wide d-block in the middle of the table. As a family they are hard, dense, high-melting metals that conduct heat and electricity well. Their partly filled d-orbitals let many of them take several oxidation states, form vividly colored compounds, and act as catalysts — which is why so much of industry, and so much of biology, runs on this block.
Properties of iron
| Atomic number (Z) | 26 |
|---|---|
| Symbol | Fe |
| Atomic mass | 55.845 |
| Category | Transition metal |
| Group | 8 |
| Period | 4 |
| Block | d-block |
| Metal / nonmetal | Metal |
| State at 25 °C | Solid |
| Electron configuration | [Ar] 3d6 4s2 |
| Electronegativity (Pauling) | 1.83 |
| Melting point | 1,538 °C (1,811.15 K / 2,800.4 °F) |
| Boiling point | 2,861 °C (3,134.15 K / 5,181.8 °F) |
| Density | 7.874 g/cm³ |
Position in the periodic table
Iron shares group 8 with Ruthenium (Ru), Osmium (Os), Hassium (Hs). Elements in the same group have the same number of outer electrons, so they tend to behave alike chemically — comparing them is one of the fastest ways to see periodic trends in action.
Physical properties
Iron melts at 1,538 °C (1,811.15 K / 2,800.4 °F) and boils at 2,861 °C (3,134.15 K / 5,181.8 °F), giving it a liquid range of about 1,323 °C at standard pressure.
Its density is 7.874 g/cm³.
See also: the interactive periodic table, how to read the periodic table, periodic trends.