Author: Jan Scholten
4.0 Cerium physical data
Metallic cerium is prepared by reduction techniques, such as by reducing cerium fluoride with calcium, or by electrolysis of molten cerium chloride or other cerium halides.
Cerium is an iron-grey lustrous metal. It is malleable, and oxidizes very readily at room temperature, especially in moist air. Except for europium, cerium is the most reactive of the rare-earth metals. It slowly decomposes in cold water, and rapidly in hot water. Alkali solutions and acids, both dilute and concentrated, attack the metal rapidly. The pure metal may ignite when scratched with a knife.
Atomic number: 58.
Discovery: 1803, Sweden, Germany, Wilhelm von Hisinger, Jöns Jacob Berzelius, Martin Klaproth.
Name: Named after the asteroid Ceres which was discovered in 1801, 2 years before the element.
Toxicology: Workers exposed to cerium have experienced itching.
sensitivity to heat, and skin lesions. Animals injected with
large doses of cerium died due to cardiovascular collapse.
Ores: The most abundant of the rare earth metals and is found
in minerals including allanite, monazite, cerite, bastnasite.
rhabdophane and hydroxyl-bastnasite. There are large deposits found in India, Brazil and the USA.
1. Component of mischmetal, used in the manufacture of pyrophoric alloys for cigarette lighters; CeFe is used in fire stones.
2. Cerium oxide is an important constituent of incandescent gas mantles and is a catalyst in “self-cleaning” ovens. In this application it is incorporated into oven walls to prevent the collection of cooking residues.
3. Cerium sulfate is used extensively as a volumetric oxidizing agent in quantitative analysis.
4. Glass, both as a component and as a decolorizer.
5. Cerium oxide is used as a glass polishing agent instead of rouge, as it is much faster at polishing glass surfaces.
6. Carbon-arc lighting with other rare-earth elements, especially in the motion picture industry.
7. Catalyst in petroleum refining and organic synthesis.
8. Metallurgical and nuclear applications.
9. CeO2 is used in car catalysts.
10. CeTbMgAlO, La Ce Tb PO4, CeGdTbMgBO3 are used in fluorescent substances.
12. Permanent magnets.
13. Added to cast irons opposes graphitization and produces a malleable iron.
13. In steels cerium can help reduce sulfides and oxides and degasifies.
14. Cerium is used in stainless steel as a precipitation-hardening agent.
15. 3 to 4% cerium added to magnesium alloys, along with 0.2 to 0.6% zirconium, helps refine the grain and give sound casting of complex shapes. It also adds heat resistance to magnesium castings.