PTL:Cerium
From ChemEd Collaborative
| Symbol: | Ce |
|---|---|
| Atomic Number: | 58 |
| Atomic Weight: | 140.115(4) |
| Electron Configuration: | [Xe] 4f1 5d1 6s2 |
| Atomic Radius: | 182.5pm |
| Melting Point: | 798°C |
| Boiling Point: | 3424°C |
| Heat of Fusion: | 5.46kJ/mol |
| Heat of Vaporization: | 414.0kJ/mol |
| Specific Heat Capacity: | 0.19J/gK |
Cerium is a metal and a member of the lanthanide or rare earth series of elements, which stretches from lanthanum (La) through lutetium (Lu). It has two common oxidation numbers: +3 and +4.In the solid state, the metal has a face-centered cubic structure.
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Discovered
Berzelius and the Swedish mineralogist Hisinger discovered an oxide of cerium in a mineral found in Sweden in 1803. Hisinger was wealthy and a member of Swedish nobility. He owned the mines from which the minerals came, and he supported Berzelius in some of the latter's early work.
Name
The element was named for the planetoid Ceres, which had been recently discovered.
Found
Cerium is the most abundant of the rare earth metals in the earth's crust. The chief source of rare earth elements is bastnasite, Ln2 F3 (CO 3)2, a fluorocarbonate (where Ln symbolizes any of the lanthanides, but chiefly Ce).
Prepared
The metal is prepared from its halides by reduction with Ca or Li or by electrolysis.
Reactions
The metal resembles steel in its appearance. Although the freshly prepared metal has a bright surface, it is readily tarnished by oxidation to give Ce2O3 or, in moist air, to give Ce(OH)3. The metal and its alloys are strongly pyrophoric - they burn in air - when scratched or sawed.
Cerium is the most reactive lanthanide, except for europium, and will ignite if scratched with a knife. It is attacked slowly by cold water, but more rapidly by hot water.
Cerium dissolves in dilute mineral acids and is attacked by alkaline solutions. Above 200° C it reacts vigorously with chlorine, bromine, and iodine to give CeX3. It also reacts directly with C, S, N2, and B at high temperatures.
Uses
Cerium-containing compounds are used in the form of rare earth mixtures as polymerization catalysts (26%); in metallurgical applications (43%); and in the ceramics and glass industry (31%) (as [glass polishing and coloring agents]).
CeO2 is also finding use as a catalyst in "self-cleaning ovens". It is incorporated into the oven walls and prevents the accumulation of cooking residues.
Cerium compounds have also been used as automobile exhaust catalysts.
Emission Spectra
This is the emission spectra for Cerium.
