• Name: Thulium

  • Symbol: Tm

  • Number of Energy Levels: 6

  • Electrons on the outer energy level: 2

  • Atomic Number: 69

  • Atomic Mass: 168.9342 Amu

  • Protons / Electrons: 69

  • Neutrons: 100

  • Density: 9.321 g/cm3

  • Classification: Rare Earth

Top 11 interesting facts about Thulium

  • Thulium was discovered in 1879 by Per Theodor Cleve. Its name derives from the word "Thule" which is the ancient name for Scandinavia.
  • Thulium's melting point is at 1545.0 C (1818.15 K, 2813.0 F) and its boiling point is at 1727.0 C (2000.15 K, 3140.6 F).
  • Thulium is a silvery-gray, soft, malleable, and ductile metal and it slowly reacts with air and water (slowly with cold water and quickly with hot water).
  • Thulium can be cut with a knife.
  • Thulium has a very high price tag and it is very rare.
  • Thulium can not be found freely in nature but it is found in minerals with other elements, particularly in mineral monazite and xenotime.
  • Thulium is the penultimate most abundant element of the lanthanides.
  • Thulium's only stable isotope is thulium-169 which is the most abundant isotope.
  • Thulium is mainly produced in China.
  • Thulium is used in the following applications: lasers used in military and medicine, portable x-ray devices, cancer treatment, industrial radiography, high-temperature superconductors, and part of euro banknotes against counterfeiting.
  • Thulium has no known biological role and it is not considered toxic.