Lutetium (Lu)

Silvery-white rare-earth metal which is relatively stable in air. It happens to be the most expensive rare-earth metal. Its found with almost all rare-earth metals, but is very difficult to separate from other elements. Least abundant of all natural elements. Used in metal alloys, and as a catalyst in various processes. There are two natural, stable isotopes, and seven radioisotopes, the most stable being Lu-174 with a half-life of 3.3 years. The separation of lutetium from Ytterbium was described by Georges Urbain in 1907. It was discovered at approximately the same time by Carl Auer von Welsbach. The name comes from the Greek word lutetia which means Paris.
Atomic Number71
Atomic Weight174.9668
Mass Number175
Protons71 p+
Neutrons104 n0
Electrons71 e-
Lutetium sublimed dendritic and 1cm3 cube.jpg Animated Bohr Model Enhanced Bohr Model Bohr Model Orbital Diagram


Atomic Radius
175 pm
Atomic Volume
Covalent Radius
162 pm
Metallic Radius
Ionic Radius
86.1 pm
Crystal Radius
100.1 pm
Van der Waals radius
224.00000000000003 pm
9.84 g/cm³
Boiling Point
3,668 K
Melting Point
1,936 K
Electrons per shell2, 8, 18, 32, 9, 2
0.8170986933369 eV/particle
Proton Affinity
992 kJ/mol
Electron Affinity
Ionization Potential
5.425871 eV/particle
Heat of Vaporization
414 kJ/mol
Heat of Fusion
Heat of Formation
427.6 kJ/mol
Molar Heat Capacity
26.86 J/(mol K)
Specific Heat Capacity
0.154 J/(g⋅K)
Thermal Conductivity
Gas Basicity
970.6 kJ/mol
Dipole Polarizability
137 a₀
C6 Dispersion Coefficient
Oxidation States3
Crystal StructureSimple Hexagonal (HEX)
Lattice Constant
3.51 Å
Bulk Modulus
Electrical Resistivity
Electron Configuration[Xe] 4f14 5d1 6s2
Magnetic Ordering
Magnetic Susceptibility
Poisson Ratio
Shear Modulus
Young's Modulus
Alternate Names
Adiabatic Index
Electric Conductivity
Critical Pressure
Critical Temperature
Curie Point
Magnetic Susceptibility
Neel Point
Neutron Cross Section
Neutron Mass Absorption
Gas Phase
Quantum Numbers
Refractive Index
Space Group
Speed of Sound
Superconducting Point
Thermal Expansion
Valence Electrons
CategoryLanthanides, Transition metals
CAS Group
Glawe Number19
Mendeleev Number41
Pettifor Number21
Geochemical Classrare earth & related
Goldschmidt Classlitophile
Decay Mode
Abundance in Earth's crust
0.8 mg/kg
Abundance in Oceans
0.00000015 mg/L
Abundance in Human Body
Abundance in Meteor
Abundance in Sun
Abundance in Universe1×10-8%

Isotopes of Lutetium

Stable Isotopes
175Lu 176Lu
Unstable Isotopes
150Lu 151Lu 152Lu 153Lu 154Lu 155Lu 156Lu 157Lu 158Lu 159Lu 160Lu 161Lu 162Lu 163Lu 164Lu 165Lu 166Lu 167Lu 168Lu 169Lu 170Lu 171Lu 172Lu 173Lu 174Lu 177Lu 178Lu 179Lu 180Lu 181Lu 182Lu 183Lu 184Lu


French chemist Georges Urbain successfully separated lutetium from ytterbia in 1907 in Paris. Austrian scientist Carl Auer von Welsbach and American chemist Charles James also succeeded in isolating lutetium independently in the same year. Pure lutetium metal was first produced in 1953. Lutetia is the ancient name for Paris

DiscoverersGeorges Urbain
Discovery LocationFrance
Discovery Year1907
Name OriginNamed for the ancient name of Paris, Lutecia.
Lutetium is considered to be non toxic
Lutetium was the last natural rare earth element to be discovered


Lutetium oxide is used to make catalysts for cracking hydrocarbons in the petrochemical industry. Lutetium aluminum garnet has been proposed for use as a lens material in high refractive index immersion lithography. Lutetium is used as a phosphor in LED light bulbs. It has no practical applications.


Found with ytterbium in gadolinite and xenotime. Usually obtained from monazite sand which is ofter 50% rare earth by weight and 0.003% lutetium.