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Lutetium (Lu)

Lutetium is a chemical element of the periodic table with chemical symbol Lu and atomic number 71 with an atomic weight of 174.967 u and is classed as lanthanide. Lutetium is solid at room temperature.

Lutetium in the periodic table

Atomic number71
AppearanceSilvery white
Color Silver
Number of protons71 p+
Number of neutrons104 n0
Number of electrons71 e-
From Wikipedia, the free encyclopediaLutetium is a chemical element with symbol Lu and atomic number 71. It is a silvery white metal, which resists corrosion in dry, but not in moist air. It is considered the first element of the 6th-period transition metals and the last element in the lanthanide series, and is traditionally counted among the rare earths.

Physical properties

Phase at STPSolid
Density9.841 g/cm3
Atomic weight174.967 u

Thermal properties

Melting point1925 K
1651.85 °C
3005.33 °F
Boiling point3675 K
3401.85 °C
6155.33 °F
Heat of vaporization355 kJ/mol

Atomic properties

Electronegativity (Pauling Scale)1.27
Electron affinity33.4 kJ/mol
Oxidation states0, +1, +2, +3
(a weakly basic oxide)
Ionization energies
  1. 523.5 kJ/mol
  2. 1340 kJ/mol
  3. 2022.3 kJ/mol
  4. 4370 kJ/mol
  5. 6445 kJ/mol

Electron configuration for lutetium

Electron configuration
Shorthand configuration
[Xe] 4f14 5d1 6s2
Electron configuration
Full configuration
1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d1 6s2
Electron configuration chart
Electrons per shell2, 8, 18, 32, 9, 2
Valence electrons 2
Valency electrons 3
Bohr model
LutetiumElectron shell for Lutetium, created by Injosoft ABLu
Figure: Shell diagram of Lutetium (Lu) atom.
Orbital Diagram

The history of Lutetium

DiscoveryCarl Auer von Welsbach, Georges Urbain (1906)
First isolationCarl Auer von Welsbach (1906)
Named byGeorges Urbain (1906)
Discovery of lutetium
Lutetium was independently discovered in 1907 by French scientist Georges Urbain, Austrian mineralogist Baron Carl Auer von Welsbach, and American chemist Charles James. All of these researchers found lutetium as an impurity in the mineral ytterbia, which was previously thought to consist entirely of ytterbium. The dispute on the priority of the discovery occurred shortly after, with Urbain and Welsbach accusing each other of publishing results influenced by the published research of the other; the naming honor went to Urbain, as he had published his results earlier. He chose the name lutecium for the new element, but in 1949 the spelling was changed to lutetium. In 1909, the priority was finally granted to Urbain and his names were adopted as official ones; however, the name cassiopeium (or later cassiopium) for element 71 proposed by Welsbach was used by many German scientists until the 1950s.


List of unique identifiers for Lutetium in various chemical registry databases
CAS Number7439-94-3
ChemSpider ID22371
EC number231-103-0
PubChem CID Number23929