|Uppsala—Per Teodor Cleve elements|
- 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.
- 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.