Lutetium (Lu)

Stable isotopes of lutetium available from ISOFLEX

Isotope Z(p) N(n) Atomic Mass Natural Abundance Enrichment Level Chemical Form
Lu-175  71  104  174.940768 97.41%  99.80%  Oxide
Lu-176  71  105  175.942683 2.59%  60.00-84.60% Oxide

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Lutetium was discovered in 1907 by Georges Urbain and Carl Auer von Welsbach. Its name originates with the Latin Lutetia, the name of a Roman town on the site of modern-day Paris.

Lutetium is a silvery-white, lustrous metal with a hexagonal close-packed structure. It is soft, ductile and slightly paramagnetic. It reacts slowly with water and is soluble in dilute acids. In aqueous media, lutetium occurs as tripositive Lu3+ ion. Aqueous solutions of all its salts are colorless, while in dry form they are white crystalline solids. Lutetium's soluble salts — such as chloride, bromide, iodide, nitrate, sulfate and acetate — form hydrates upon crystallization. The oxide, hydroxide, fluoride, carbonate, phosphate and oxalate of the metal are insoluble in water. The metal dissolves in acids, forming the corresponding salts upon evaporation of the solution and crystallization.

There is very limited commercial application for lutetium. The metal emits beta particles after thermal neutron activation, and it is used to catalyze organic reactions as well as for dating meteorites. Stable lutetium can be used in petroleum cracking in refineries, as well as for alkylation, hydrogenation and polymerization applications. Its synthetic isotope Lutetium-177, when bound to octreotate, is used experimentally in targeted radionuclide therapy for neuroendocrine tumors.

Properties of Lithium

Name Lutetium
Symbol Lu
Atomic number 71 
Atomic weight 174.97 
Standard state Solid at 298 ºK 
CAS Registry ID 7439-94-3 
Group in periodic table
Group name N/A 
Period in periodic table
Block in periodic table d-block 
Color Silvery white 
Classification Metallic 
Melting point 1663 °C
Boiling point 3395 °C
Vaporization point 3402 ºC
Thermal conductivity 16.4 W/(m·K) at 298.2 °K
Electrical resistivity 79.0 µΩ·cm at 25 °C 
Electronegativity 1.2 
Specific heat 0.155 J/g mol at 25 °C 
Heat of vaporization 415 kJ·mol-1 at 3395 °C
Heat of fusion 22 kJ·mol-1
Density of liquid 9.3 g/cm3 at 1663 °C 
Density of solid 9.84 g/cm3
Electron configuration [Xe]4f145d16s2 
Atomic radius 1.7349 Å (coordination number 12) 
Ionic radius Lu3+: 0.85 Å
Oxidation state +3