cerium

• Description
• General information
• Physical data
• Radii
• Electronegativities
• Solid state structure
• Temperatures
• Enthalpies
• Ionization Enthalpies
• Isotopes
• Further information

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 (R_max)

orbital	s	p	d	f
radius	216.9	no data	112.5	36.7

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.

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
1st	528
2nd	1047
3rd	1949
4th	3543

Isotopes

This section gives some data for naturally occurring isotopes.

Nominal mass	Accurate mass	% natural abundance
136Ce	135.907140 (50)	0.19 (1)
138Ce	137.905985 (12)	0.25 (1)
140Ce	139.905433 (4)	88.48 (10)
142Ce	141.909241 (4)	11.08 (10)

Further Information

• Additional information about WebElements 1.2.2
• This is a licensed copy (here is the full list) of WebElements 1.2.2 and contains a subset of the material contained within the main version of WebElements (version 2)
• For further information please try WebElements version 2
• Sheffield Chemdex: perhaps the largest internet chemistry directory
• Sheffield Chemputer: interactive chemistry calculators on the WWW