WebElements

Periodic Table

europium

Atomic number: 63
Atomic weight: 151.964
Symbol: Eu
Group number: (lanthanide)
Electronic configuration: [Xe].4f7.6s2

Description

Europium ignites in air at about 150 to 180°C. Europium is about as hard as lead and is quite ductile. It is the most reactive of the rare earth metals, quickly oxidising in air. It resembles calcium in its reaction with water. It is used in television screens to produce a red colour.

General information

Discoveror: Eugene Demarcay
Date discovered: 1901
Discovered at: France
Meaning of name: Named after "Europe"

Physical data

Standard state: solid at 298 K
Colour: silvery white
Density of solid at ambient temperature/kg m-3: 5244
Molar volume/cm3: 28.97

Radii /pm

Atomic: 231
Covalent (single bond):
Pauling radius for the ion [Eu]-: no data

Valence shell orbital radius maxima (Rmax)
orbital s p d f
radius214.0no datano data31.0

Electronegativities

Both values are quoted on the Pauling scale.

Pauling: no data
Allred Rochow: 1.01

Crystal Structure

structure: bcc (body-centred cubic)

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: 1099
boiling point: 1800

Enthalpies /kJ mol-1

fusion: 9.4
vaporization: 177

single bond enthalpies:
Eu-F Eu-Cl Eu-Br Eu-I Eu-Eu
no data no data no data 272 33.5

Ionization enthalpies /kJ mol-1

Number Enthalpy
1st547
2nd1085
3rd2400
4th4110
5th6100

Isotopes

This section gives some data for naturally occurring isotopes.
Nominal mass Accurate mass % natural abundance
151Eu150.919702 (8)47.8 (15)
153Eu152.921225 (4)52.2 (15)

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/Eu.html