Atomic number: 71

Symbol: Lu

Category: lanthanoid metal

Density at 25°C: solid: density: 9.841 g·cm−3

Lutetium is the last of the so called rare earth elements or lanthenoids. This element is also quite difficult to purify from other rare earth elements it is found with. As a result it tends not to have very widespread use. 

High purity lutetium dendrites from sublimation. image: adapted from wikipedia

Use, natural applications or common combinations: 

  • sometimes used as a catalyst for petroleum industry
  • Lutetium tantalate (LuTaO4) is the densest known stable white material (density 9.81 g/cm3)

Basic characteristics:

  • Standard atomic weight: 174.9668(1)
  • Melting point:  1652 °C
  • Boiling point: 3402 °C
  • Radioactivity: most naturally stable
    • 176Lu (2.59%) with a half life of 3.78×1010 years decays via beta-