Atomic Properties of Ce
- Atomic Number of Ce
- 58
- Atomic Mass of Ce
- 140.1200 u
- Electron Configuration
- [Xe] 4f1 5d1 6s2
- Electronegativity
- 1.12
- Block
- f-block
- Group
- —
- Period
- 6
Cerium arrived in 1803 through two independent discoveries: Martin Heinrich Klaproth in Germany and Jöns Jacob Berzelius with Wilhelm Hisinger in Sweden. They named it for Ceres, the recently discovered object then called an asteroid and now classified as a dwarf planet. A new member of the heavens lent its name to a new substance on Earth.
Among the lanthanides, cerium is the most abundant in Earth's crust. It is also unusual because both Ce3+ and Ce4+ are chemically accessible. Cerium oxide can store and release oxygen as conditions change, a redox flexibility used in catalytic converters to help manage pollutants in vehicle exhaust. The same oxide's fine particles serve as a precision polishing material for glass.
The famous spark comes from ferrocerium, an alloy rich in cerium and other elements. Scraping it sheds tiny reactive particles that ignite in air, producing the shower used by lighter “flints” and fire starters. The alloy is not a stone flint, and the useful ignition behavior does not mean every cerium compound bursts into flame.
Cerium metal itself tarnishes readily and requires careful handling. Its compounds also color and modify glass, while industrial catalysts exploit their surface chemistry.
This Luminary has two settings because its electrons permit two common oxidation states. That switch links an entertaining spark to serious pollution control: controlled reactivity at the right scale can start a flame, smooth a lens, or help an exhaust system convert unwanted gases.