Lutetium
The hardest, densest lanthanide, used in PET scan detectors.
Inside the Lutetium atom
Switch between Bohr and Quantum Cloud modes to compare a simple teaching model with a more realistic probability-based view, and follow the guided tour to explore the Lutetium atom step by step.
Electron configuration
[Xe] 4f14 5d1 6s2
A neutral Lutetium atom has 71 electrons (equal to its proton count). Choosing a different isotope above changes only the neutron count.
Shell distribution
Electrons fill inner shells before outer ones; the outermost (valence) shell drives the element's chemistry.
Physical & atomic properties
- State (room temp)
- Solid
- Melting point
- 1925 K (1652 °C)
- Boiling point
- 3675 K (3402 °C)
- Density
- 9.84 g/cm³
- Electronegativity
- 1.27 Pauling
- Atomic radius
- 175 pm
- 1st ionization energy
- 524 kJ/mol
- Category
- Lanthanides
Discovery & naming
- Discovered
- 1907
- Discovered by
- Georges Urbain
- Origin of name
- Latin 'Lutetia', for Paris.
Notable uses
PET-scan detectors and petroleum-cracking catalysts.
Where Lutetium comes from
Neutron star mergers
Mostly an r-process element, with a smaller contribution from slow neutron capture.
Simplified origin map — many elements form through more than one astrophysical pathway.
Summary
- Atomic number
- 71
- Atomic mass
- 174.97
- Category
- Lanthanides
- Group · Period
- — · 6
- Block
- f-block
- Shells
- 2 · 8 · 18 · 32 · 9 · 2