15.0 Thulium physicalThulium is the least abundant of the lanthanides, but more common than Silver, Mercury or
Iodum. Its metal is easy to work, has a bright silvery-gray luster and can be cut by a knife. It also has some corrosion resistance in dry air and good ductility. Naturally occurring thulium is made entirely of the stable isotope Tm-169.
Atomic Number: 69.
Symbol: Tm.
Discovery: 1879 by P.T. Cleve at Uppsala, Sweden.
Name: after Thule, an old name for Scandinavia.
Toxicology: low-to-moderate acute toxicity
Ore: monazite.
Uses1. Laser: high production costs have prevented other commercial uses from being developed.
2. Magnets: Tm-169 has potential use in ceramic magnetic materials called ferrites, which are used in microwave equipment.
3. Roentgen amplifying foils: YTa + Tm, or LaOBr + Tm:.
4. Radioactivity: when stable thulium (Tm-169) is bombarded in a nuclear reactor it can later serve as a radiation source in portable
X-ray devices.
5. Radioactivity: The unstable Tm-171 could possibly be used as an energy source.