Atomic number: 68

Symbol: Er

Category: lanthanoid metal

Density at 25°C: solid: density: 9.066 g·cm−3

As with other rare earth elements small amounts of this element are used for colouring glass, particularly certain kinds of dermal lasers. It is also important in fibre optic communications. 

Sample of erbium metal. image:

Use, natural applications or common combinations: 

  • lasers
  • found in monazite sand ores
  • specialised cryogenic (ultra cold temperature) applications.

Basic characteristics:

  • Standard atomic weight: 167.259(3)
  • Melting point:  1529 °C
  • Boiling point: 2868 °C
  • Radioactivity: most naturally stable
  • 162Er is a little radioactive with a half life of more than >1.4×1014 years