---
title: "Iron (Fe) — element 26"
description: "Iron is element 26, symbol Fe, atomic weight 55.845. Configuration, properties, uses and neighbours."
url: https://atoneplace.net/element/iron/
site: "At One Place"
---

# Iron (Fe)

**Iron — element 26: Fe**

55.845 u · Transition metal · period 4, group 8

Iron is the most abundant element on Earth by mass, most of it in the core, and the Earth's magnetic field is generated by that molten iron circulating. It is also the end of the line for stellar fusion: iron-56 has the highest binding energy per nucleon of any common nucleus, so fusing it releases no energy and a massive star that reaches an iron core collapses within seconds. The transition from bronze to iron around 1200 BC was less about iron being better — early iron was worse than good bronze — than about iron ore being everywhere while tin was not.

## Properties

- **Atomic number:** 26
- **Symbol:** Fe
- **Standard atomic weight:** 55.845 u
- **Category:** Transition metal
- **Group:** 8
- **Period:** 4
- **Block:** d-block
- **Electron configuration:** [Ar] 4s² 3d⁶
- **Electrons per shell:** 2, 8, 14, 2
- **Melting point:** 1,811 K — 1537.8 °C — 2800.1 °F
- **Boiling point:** 3,134 K — 2860.8 °C — 5181.5 °F
- **Density:** 7.874 g/cm³
- **Electronegativity:** 1.83 (Pauling)
- **Oxidation states:** +3, +2
- **Discovered:** Known since antiquity

## Electron configuration

- **Full:** 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁶
- **Noble gas shorthand:** [Ar] 4s² 3d⁶
- **Shells:** K: 2 · L: 8 · M: 14 · N: 2

## What it is used for

- Steel — buildings, bridges, ships, cars, tools, tin cans
- Cast iron for engine blocks, cookware and manhole covers
- Transformer and motor cores, as electrical steel
- Iron supplements and fortified flour and cereal
- Iron oxide pigments — most reds, browns and yellows in paint

> Iron's magnetism disappears above its Curie point of 1,043 K, well below its melting point — a red-hot horseshoe is not magnetic.

## Neighbours in the table

| Z | Element | Symbol | Mass |
| --- | --- | --- | --- |
| 24 | Chromium | Cr | 51.996 |
| 25 | Manganese | Mn | 54.938 |
| 26 | Iron ← | Fe | 55.845 |
| 27 | Cobalt | Co | 58.933 |
| 28 | Nickel | Ni | 58.693 |

## Group 8

Elements in the same group share their outer electron count, which is why they behave similarly in reactions. Iron sits in group 8 with ruthenium, osmium, hassium.

## Common questions

### What is the atomic number of iron?

26. That is the number of protons in its nucleus, which is what defines the element.

### What is the symbol for iron?

Fe.

### What is the electron configuration of iron?

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁶, or [Ar] 4s² 3d⁶ in noble-gas shorthand.

### What is the melting point of iron?

1,811 K — 1537.8 °C — 2800.1 °F

## Related pages

- [Chromium (Cr)](https://atoneplace.net/element/chromium/)
- [Manganese (Mn)](https://atoneplace.net/element/manganese/)
- [Cobalt (Co)](https://atoneplace.net/element/cobalt/)
- [Nickel (Ni)](https://atoneplace.net/element/nickel/)
- [Ruthenium (Ru)](https://atoneplace.net/element/ruthenium/)
- [Osmium (Os)](https://atoneplace.net/element/osmium/)
- [Hassium (Hs)](https://atoneplace.net/element/hassium/)

## Sources

- Official vendor product documentation — At One Place (/about/)