---
title: "Cerium (Ce) — element 58"
description: "Cerium is element 58, symbol Ce, atomic weight 140.12. Configuration, properties, uses and neighbours."
url: https://atoneplace.net/element/cerium/
site: "At One Place"
---

# Cerium (Ce)

**Cerium — element 58: Ce**

140.12 u · Lanthanide · period 6

Cerium is the most abundant rare earth, more common in the crust than copper, which makes the name "rare earth" a historical accident: they were called rare because they were hard to separate, not because there is little of them. It is the only lanthanide with a stable +4 state, which is what lets a catalytic converter store and release oxygen as the engine's mixture swings rich and lean. A lighter flint is mostly cerium: the alloy is soft and pyrophoric, so a struck spark is a shaving of metal burning in mid-air.

## Properties

- **Atomic number:** 58
- **Symbol:** Ce
- **Standard atomic weight:** 140.12 u
- **Category:** Lanthanide
- **Period:** 6
- **Block:** f-block
- **Electron configuration:** [Xe] 6s² 4f¹ 5d¹
- **Electrons per shell:** 2, 8, 18, 19, 9, 2
- **Melting point:** 1,071 K — 797.9 °C — 1468.1 °F
- **Boiling point:** 3,697 K — 3423.8 °C — 6194.9 °F
- **Density:** 6.77 g/cm³
- **Electronegativity:** 1.12 (Pauling)
- **Oxidation states:** +4, +3
- **Discovered:** 1803 by Jöns Jacob Berzelius and Wilhelm Hisinger, and independently Martin Heinrich Klaproth

## Electron configuration

- **Full:** 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹ 5d¹
- **Noble gas shorthand:** [Xe] 6s² 4f¹ 5d¹
- **Shells:** K: 2 · L: 8 · M: 18 · N: 19 · O: 9 · P: 2

## What it is used for

- Glass and silicon wafer polishing — cerium oxide is the standard abrasive
- The oxygen buffer in three-way catalytic converters
- Lighter flints, as the main component of mischmetal
- UV-absorbing glass for car windows and display cases
- Self-cleaning oven coatings

## Hazards

- Cerium metal turnings are pyrophoric and can ignite from friction alone

> Anomalous electron configuration: [Xe] 6s² 4f¹ 5d¹ rather than the predicted 6s² 4f². Named after the asteroid Ceres, discovered two years earlier.

## Neighbours in the table

| Z | Element | Symbol | Mass |
| --- | --- | --- | --- |
| 56 | Barium | Ba | 137.33 |
| 57 | Lanthanum | La | 138.91 |
| 58 | Cerium ← | Ce | 140.12 |
| 59 | Praseodymium | Pr | 140.91 |
| 60 | Neodymium | Nd | 144.24 |

## Common questions

### What is the atomic number of cerium?

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

### What is the symbol for cerium?

Ce.

### What is the electron configuration of cerium?

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹ 5d¹, or [Xe] 6s² 4f¹ 5d¹ in noble-gas shorthand.

### What is the melting point of cerium?

1,071 K — 797.9 °C — 1468.1 °F

## Related pages

- [Barium (Ba)](https://atoneplace.net/element/barium/)
- [Lanthanum (La)](https://atoneplace.net/element/lanthanum/)
- [Praseodymium (Pr)](https://atoneplace.net/element/praseodymium/)
- [Neodymium (Nd)](https://atoneplace.net/element/neodymium/)

## Sources

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