Cerium
Element 58 · Lanthanide
Cerium is the workhorse of the lanthanides and the most plentiful of them all. It is unusual in reaching the +4 oxidation state in solution, which makes cerium(IV) compounds strong oxidizing agents used in analytical chemistry. The metal itself is soft and ductile, tarnishes quickly, and throws sparks when scratched — the property behind lighter flints.
Industry uses cerium everywhere from catalytic converters and self-cleaning oven coatings to the polishing powder that gives glass and mirrors their finish. Cerium oxide nanoparticles also block ultraviolet light in some glass and coatings.
Key facts
| Atomic number | 58 |
|---|---|
| Atomic weight | 140.12 |
| Category | Lanthanide |
| Group / Period | — / 6 |
| Block | f |
| Electron configuration | 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f1 5d1 |
| Common oxidation states | +3, +4 |
| State at STP | Solid |
| Electronegativity | 1.12 |
| Density | 6.77 g/cm³ |
| Melting point | 798 °C |
| Boiling point | 3443 °C |
Occurrence
Cerium is the most abundant lanthanide, found in monazite, bastnasite, and cerite ores, always mixed with other rare earth metals.
Applications
Lighter flints and sparking alloys
Catalytic converters and oven coatings
Glass and mirror polishing powder
UV-blocking glass
Common compounds
- cerium(IV) oxide
- cerium(III) chloride
- cerium(III) sulfate
Cerium is actually more abundant in Earth's crust than copper — ‘rare earth’ describes how hard these metals are to separate, not how scarce they are.
Data source: IUPAC standard atomic weights 2021