Cerium

Name: Cerium
Symbol: Ce
Atomic Number: 59
Mass fraction of the earth’s shell: 43 ppm
Melting Point: 795 °C
Boiling Point: 3470 °C
Electrical Conductivity: 1,15· 106 A·V−1·m−1

Name: Cerium
Symbol: Ce
Atomic Number: 59
Mass fraction of the earth’s shell: 43 ppm
Melting Point: 795 °C
Boiling Point: 3470 °C
Electrical Conductivity: 1,15· 106 A·V−1·m−1

HISTORY

 

Jöns Jacob Berzelius
Jöns Jacob Berzelius
Cerium was discovered by Jöns Jacob Berzelius and Wilhelm von Hiesiger in Stockholm in 1803. When naming it, they were inspired by the dwarf planet Ceres. Almost at the same time, Martin Klaproth in Berlin examined the same planet and discovered a previously unknown oxide.

Carl Gustav Mosander, in turn, succeeded in producing the element by reducing the chloride with sodium. In 1839, Mosander was able to prove that the ochroite earth discovered by Klaproth was not pure cerium oxide but a mixture of several earths. In the process, he also discovered lanthanum.

CHARACTERISTICS & EXTRACTION

In the table of the most reactive elements, the silvery-white shining metal ranks 2nd behind europium. If the yellow oxide layer of the metal is damaged, it ignites. If heated to 150°C, it burns with a violent glowing to form cerium dioxide. If it comes into contact with water, it reacts to form cerium hydroxide. Finely distributed, the metal can heat up and ignite just like that. Industry has uses for cerium in some areas. In aluminium alloys, cerium brings strength and ductility to a higher level. Glass and enamel are coloured with the help of cerium. Pyrophoric cerium alloys make sparks fly in lighters or gas lighters.

It is also used in UV filters for special glass and windscreens.
Monazite sand is needed to produce cerium. First, the ore is enriched and decomposed with sulphuric acid. Sulphates are obtained, which are precipitated in ice water with oxalic acid as oxalates and converted into the oxides by annealing. Then the cerium oxide is separated. A reaction with hydrogen chloride yields cerium(III) chloride. The last step is either fused-salt electrolysis, or reduction with calcium or magnesium. Both methods convert the cerium chloride into cerium.
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