ELEMENTLE

Element 58 · Lanthanide

Cerium

Period 6

Cerium is a chemical element with symbol Ce and atomic number 58. It is a soft, silvery, ductile metal which easily oxidizes in air. Cerium was named after the dwarf planet Ceres (itself named after the Roman goddess of agriculture).

Three reasons Cerium stands out

  1. 1

    Used in catalytic converters and glass.

  2. 2

    Its oxide is the main ingredient in the polishing compound used to grind and finish optical lenses and gemstones.

  3. 3

    It is the most abundant of all the rare-earth elements, despite being in the "rare" category.

A rare earth common enough for sparks

Cerium is the most abundant lanthanide. It switches readily between two oxidation states, allowing cerium oxide to store and release oxygen in catalytic converters. Mischmetal rich in cerium makes lighter flints; scraping it creates hot sparks rather than merely exposing a glowing ember.

Cerium at a glance
Atomic number / protons58
SymbolCe
Family (Elementle)Lanthanide
Classification (PubChem)Lanthanide
Period6
GroupLanthanide / actinide series
Atomic mass (u)140.116
Standard stateSolid
Electron configuration[Xe]6s2 4f1 5d1
Reported oxidation states+4, +3
Electronegativity (Pauling)1.12
Atomic radius (pm)235
First ionization energy (eV)5.539
Electron affinity (eV)0.5
Density (g/cm³)6.770
Melting point1071 K (797.85 °C)
Boiling point3697 K (3,423.85 °C)
Discovery (PubChem)1803

Values are reference data, not a specification for every temperature, pressure, or allotrope. Unknown properties are left unavailable. Superheavy-element predictions remain uncertain.

Sources & further reading

PubChem: Cerium · Cerium on Wikipedia

The introduction and original editorial story are adapted from Wikipedia contributors via Periodic-Table-JSON. Element descriptions and their adaptations are available under CC BY-SA 3.0. Numerical attributes use the PubChem periodic-table dataset, retrieved September 22, 2026.