Thulium (thew-lee-əm)
is a chemical element that has the symbol Tm and an atomic
number of 69. It has an atomic weight of 168.93421.
Things you might not know about
Thulium:
- The price per kilogram has oscillated between
US$ 4,600 and $13,300 in the period from 1959 to 1998 for 99.9%
purity.
- Thulium was discovered by Swedish chemist Per
Teodor Cleve in 1879 its named after Thule, Scandinavia.
- Despite its high cost, portable X-ray devices
use thulium that has been bombarded in a nuclear reactor as a
radiation source. These sources are available for about one year,
as tools in medical and dental diagnosis, as well as to detect
defects in inaccessible mechanical and electronic components.
See GC2XAY2 - Hydrogen, for an explanation
about this series of caches.