Periodic Table


Atomic number: 71
Atomic weight: 174.967
Symbol: Lu
Group number: (lanthanide)
Electronic configuration: [Xe].4f14.5d1.6s2


Pure metal lutetium has been isolated only in recent years and is one of the more difficult to prepare. It can be prepared by the reduction of anhydrous LuCl3 or LuF3 by an alkali or alkaline earth metal.

The metal is silvery white and relatively stable in air. It is a rare earth metal and perhaps the most expensive of all rare elements. It is found in small amounts with all rare earth metals, and is very difficult to separate from other rare elements.

General information

Discoveror: Georges Urbain and Carl Auer von Welsbach
Date discovered: 1907
Discovered at: France, Germany
Meaning of name: From the Greek word "Lutetia" meaning "Paris"

Physical data

Standard state: solid at 298 K
Colour: silvery white
Density of solid at ambient temperature/kg m-3: 9841
Molar volume/cm3: 17.78

Radii /pm

Atomic: 217
Covalent (single bond):
Pauling radius for the ion [Lu]-: no data

Valence shell orbital radius maxima (Rmax)
orbital s p d f
radius186.7no data95.024.6


Both values are quoted on the Pauling scale.

Pauling: 1.27
Allred Rochow: 1.14

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: 1925
boiling point: 3675

Enthalpies /kJ mol-1

fusion: 22
vaporization: 414

single bond enthalpies:
Lu-F Lu-Cl Lu-Br Lu-I Lu-Lu
no data no data no data 343 142

Ionization enthalpies /kJ mol-1

Number Enthalpy


This section gives some data for naturally occurring isotopes.
Nominal mass Accurate mass % natural abundance
175Lu174.940770 (3)97.41 (2)
176Lu175.942679 (3)2.59 (2)

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/Lu.html