Lutetium (Lu)
Lanthanide · f-block · period 6
Hard, dense, silvery-white, corrosion-resistant metal.
Lutetium (symbol Lu) is chemical element number 71, a lanthanide in the lanthanide series (f-block), period 6 of the periodic table. Its standard atomic weight is 174.97 and its electron configuration is [Xe] 4f14 5d1 6s2. At room temperature it is a solid. Named after Lutetia, the Roman name for Paris.
Properties
| Atomic number | 71 |
|---|---|
| Atomic mass | 174.97 |
| Category | Lanthanide |
| Block | f-block |
| Group · Period | f-block series · 6 |
| Electron configuration | [Xe] 4f14 5d1 6s2 |
| Electrons per shell | 2, 8, 18, 32, 9, 2 |
| State at 25 °C | solid |
| Melting point | 1925 K |
| Boiling point | 3675 K |
| Density | 9.84 g/cm³ |
| Electronegativity (Pauling) | 1.27 |
| Radioactive | No |
| Origin | primordial |
| Discovered | 1907 · Georges Urbain; Carl Auer von Welsbach |
Key facts about Lutetium
- Named after Lutetia, the Roman name for Paris.
- The hardest and densest lanthanide, and one of the rarest and most expensive.
- Lutetium crystals detect the gamma rays in PET medical scanners.
- A radioactive lutetium drug is a modern targeted treatment for some cancers.
What Lutetium is used for
PET-scanner detector crystals, targeted cancer radiotherapy, petroleum cracking catalysts, rock dating.
Where it sits in the periodic table
Lutetium is in the lanthanide series, period 6, of the f-block. Its electron configuration [Xe] 4f14 5d1 6s2 means its outermost shell holds 2 electrons, which is what places it here and explains much of its chemistry. See Lutetium on the interactive table →
Lutetium — frequently asked questions
What is Lutetium used for?
PET-scanner detector crystals, targeted cancer radiotherapy, petroleum cracking catalysts, rock dating.
Is Lutetium radioactive?
No. Lutetium has at least one stable isotope and is not radioactive.
What is the electron configuration of Lutetium?
Lutetium has the electron configuration [Xe] 4f14 5d1 6s2, which is 2, 8, 18, 32, 9, 2 electrons per shell.
What group and period is Lutetium in?
Lutetium is in the lanthanide series (f-block), period 6, in the f-block. Its outer shell holds 2 electrons.
Who discovered Lutetium?
Lutetium was discovered in 1907 by Georges Urbain; Carl Auer von Welsbach.