Atomic number: 66

Symbol: Dy

Category: lanthanoid metal

Density at 25°C: solid: density: 8.540 g·cm−3

Not only is this element 'hard to get at', which what the name means,  it originally did not have many applications but now is used quite extensively in small amounts in magnetic applications for example in hard disk drives.

Sample of dysprosium metal dendrites. image: images-of-elements.com

Use, natural applications or common combinations: 

  • high-precision liquid fuel injectors
  • Dosimeters for measuring ionizing radiation

Basic characteristics:

  • Standard atomic weight: 162.500(1)
  • Melting point:  1407 °C
  • Boiling point: 2562 °C
  • Radioactivity: most naturally stable
  • 156Dy but has half life of over 1018 years