Discovery date : 1803
Discovered by: Jöns Jacob Berzelius and Wilhelm Hisinger
Origin of the name: Cerium is named for the asteroid, Ceres,
which in turn was named after the Roman God of agriculture.
Allotropes :
~>CERIUM is a chemical element with symbol Ce and atomic number 58. Cerium is a soft, ductile and silvery-white metal that tarnishes when exposed to air, and it is soft enough to be cut with a knife.
| FACT BOX | |||
| Group | Lanthanides | Melting point | 799°C, 1470°F, 1072 K |
| Period | 6 | Boiling point | 3443°C, 6229°F, 3716 K |
| Block | f | Density (g cm−3) | 6.77 |
| Atomic number | 58 | Relative atomic mass | 140.116 |
| State at 20°C | Solid | Key isotopes | 140Ce |
| Electron configuration | [Xe] 4f15d16s2 | CAS number | 7440-45-1 |
| ChemSpider ID | 22411 | ChemSpider is a free chemical structure database | |
Cerium was first identified by the Jöns Berzelius and Wilhelm Hisinger in the winter of 1803/4. Martin Klaproth independently discovered it around the same time.
Although cerium is one of the 14 lanthanoid (aka rare earth) elements it was discovered independently of them. There are some minerals that are almost exclusively cerium salts such as cerite, which is cerium silicate. A lump of this mineral had been found in 1751 by Axel Cronstedt at a mine in Vestmanland, Sweden. He sent some to Carl Scheele to analyse it but he failed to realise it was new element. In 1803, Berzelius and Hisinger examined it themselves and proved that it contained a new element.
It was not until 1875 that William Hillebrand and Thomas Norton obtained a pure specimen of cerium itself, by passing an electric current through the molten cerium chloride.