WebElements

Periodic Table

cerium

Atomic number: 58
Atomic weight: 140.116
Symbol: Ce
Group number: (lanthanide)
Electronic configuration: [Xe].4f1.5d1.6s2

Description

Metallic cerium is prepared by reduction techniques, such as by reducing cerous fluoride with calcium, or by electrolysis of molten cerous chloride or other cerous halides.

Cerium is an iron-grey lustrous metal. It is malleable, and oxidises 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 dilute and concentrated acids attack the metal rapidly. The pure metal may ignite when scratched with a knife.

It is the most abundant of the rare earth metals and is found in minerals including allanite, monazite, cerite, and bastanite. There are large deposits found in India, Brazil and the USA.

General information

Discoveror: Wilhelm von Hisinger, Jons Jacob Berzelius, Martin Klaproth
Date discovered: 1803
Discovered at: Sweden, Germany
Meaning of name: Named after the asteroid Ceres which discovered in 1801, 2 years before the element

Physical data

Standard state: solid at 298 K
Colour: silvery white
Density of solid at ambient temperature/kg m-3: 6689
Molar volume/cm3: 20.69

Radii /pm

Atomic: no data
Covalent (single bond):
Pauling radius for the ion [Ce]-: no data

Valence shell orbital radius maxima (Rmax)
orbital s p d f
radius216.9no data112.536.7

Electronegativities

Both values are quoted on the Pauling scale.

Pauling: 1.12
Allred Rochow: 1.08

Crystal Structure

structure: hcp (hexagonal close-packed)

The following CrystalMaker image represents the solid state structure. For most elements, the most stable allotrope is illustrated. Try WebElements version 2 for interactive virtual reality and CHIME images.

ball-and-stick.gif

Temperatures (/K)

melting point: 1068
boiling point: 3633

Enthalpies /kJ mol-1

fusion: 5.3
vaporization: 350

single bond enthalpies:
Ce-F Ce-Cl Ce-Br Ce-I Ce-Ce
no data no data no data 356 245.2

Ionization enthalpies /kJ mol-1

Number Enthalpy
1st528
2nd1047
3rd1949
4th3543

Isotopes

This section gives some data for naturally occurring isotopes.
Nominal mass Accurate mass % natural abundance
136Ce135.907140 (50)0.19 (1)
138Ce137.905985 (12)0.25 (1)
140Ce139.905433 (4)88.48 (10)
142Ce141.909241 (4)11.08 (10)

Further Information

Copyright 1997 Mark Winter
Department of Chemistry at the University of Sheffield, Sheffield S3 7HF, England.

The current version of this document is at http://www.shef.ac.uk/~chem/web-elements-I/Ce.html