Lutetium
Element 71 · Lanthanide
Lutetium closes the lanthanide series: the densest, hardest, and highest-melting of them all, a silvery metal that resists corrosion better than most of its neighbors. It is found only in the +3 state in compounds.
Medicine is its stage. Lutetium-based scintillator crystals detect the gamma rays in PET scanners, and the isotope lutetium-177 delivers targeted radiation that hunts down certain tumors. It also catalyzes petroleum refining and hydrogenation reactions.
Key facts
| Atomic number | 71 |
|---|---|
| Atomic weight | 174.97 |
| Category | Lanthanide |
| Group / Period | — / 6 |
| Block | f |
| Electron configuration | 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d1 |
| Common oxidation states | +3 |
| State at STP | Solid |
| Electronegativity | 1.27 |
| Density | 9.84 g/cm³ |
| Melting point | 1663 °C |
| Boiling point | 3402 °C |
Occurrence
Lutetium is one of the rarest lanthanides, recovered in small amounts from monazite and xenotime processing.
Applications
PET scan detector crystals
Lu-177 targeted cancer therapy
Petroleum refining catalysts
Research phosphors
Common compounds
- lutetium oxide
- lutetium chloride
Lutetium is named after Lutetia, the ancient Roman name for Paris — and Lu-177 is now used in targeted therapy that hunts down cancer cells.
Data source: IUPAC standard atomic weights 2021