Cerium is a metallic chemical element with the symbol Ce. It has the atomic number 58 and a commonly reported atomic mass around 140.12. Cerium is classified among the rare-earth metals and belongs to the lanthanide series; more general information about the element can be found via element resources.

Characteristics and chemistry

Cerium is silvery-white and soft relative to transition metals. It displays multiple oxidation states, most notably +3 and +4. The +4 state is more accessible for cerium than for many other lanthanides, allowing stable compounds such as cerium dioxide. Cerium compounds are often useful because of redox activity and oxygen-storage capability.

Occurrence and historical notes

Cerium occurs in a number of rare-earth minerals and is one of the more abundant lanthanides in Earth’s crust. It was recognized as a distinct element in the early 19th century during the study of rare-earth oxides; subsequent work separated cerium-containing oxides and isolated metallic forms as separation techniques improved.

Uses and applications

Cerium has a variety of industrial and scientific applications. Common uses include:

  • Automotive and industrial catalysts, where cerium oxides help in redox reactions and oxygen storage.
  • Polishing powders for glass and precision optics, using cerium(IV) oxide for its abrasive and chemical action.
  • Alloys and mischmetal formulations used in lighter flints and as additives to improve metal properties.
  • Phosphors and pigments in lighting and display technologies.

Because of its flexible chemistry, cerium plays a role in emerging technologies as a component of catalysts, fuel cells, and materials for environmental control.

Notable distinctions and safety

Among the lanthanides, cerium is notable for frequently exhibiting a +4 oxidation state and for being relatively abundant compared with some other rare-earth elements. Handling cerium and its compounds generally requires standard precautions for fine powders and reactive metals; industrial exposures are managed by common safety practices.

For more technical reference and data tables, consult specialized chemical resources and databases via the links above: general, atomic number, atomic mass, symbol, classification.