Thulium Atomic number 69 Stuff Commentary

Uppsala—Per Teodor Cleve elements

Thulium

• Thulium’s chemical symbol, Tm,
• is not a typo for Tin.
• Per Teodor Cleve discovered it
• looking for impurities in rare earth oxides.
• He found two impurities in erbia
• that he called holmia and thulia.
• Holmia was the brown oxide
• and thulia was the green one.
• He named holmia after Holmia (Stockholm)
• and thulia after Thule (Scandinavia).

Atomic number 69

• Holmium, chromium, and thulium
• make an efficent laser.
• Radioactive thulium isotopes
• power portable X-ray devices.
• Thulium fluoresces blue
• to help identify euro banknotes.

Trying

• It’s not the rarest rock on earth.
• It’s not the weirdest bird to swim or fly.
• I’m not the hairiest biped in the woods.
• I’m not the smartest primate but I try.