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|Atomic Number:||69||Atomic Symbol:||Tm|
|Atomic Weight:||168.9342||Electron Configuration:||2-8-31-8-2|
|Melting Point:||1545oC||Boiling Point:||1727oC|
|Description:||Silver colored rare earth metal.|
|Uses:||Radioactive thulium is used to power portable x-ray machines, |
eliminating the need for electrical equipment
History(Thule, the earliest name for Scandinavia) Discovered in 1879 by
- Thulium occurs in small quantities along with other rare earths in a number
- It is obtained commercially from monazite, which contains about 0.007% of
- Thulium is the least abundant of the rare earth elements, but with new
sources recently discovered, it is now considered to be about as rare as silver,
gold, or cadmium.
- Ion-exchange and solvent extraction techniques have recently permitted much
easier separation of the rare earths, with much lower costs.
- Thulium can be isolated by reduction of the oxide with lanthanum metal or by
calcium reduction of a closed container.
- The element is silver-gray, soft, malleable, and ductile, and can be cut
with a knife.
- Twenty five isotopes are known, with atomic masses ranging from 152 to 176.
- Natural thulium, which is 100% 169Tm, is stable.
- Because of the relatively high price of the metal, thulium has not yet found
many practical applications.
- 169Tm bombarded in a nuclear reactor can be used as a radiation source in
portable X-ray equipment.
- 171Tm is potentially useful as an energy source.
- Natural thulium also has possible use in ferrites (ceramic magnetic
materials) used in microwave equipment.
CostsOnly a few years ago, thulium metal was not obtainable at any
cost; in 1985 the oxide sold for $3400/kg. Thulium metal costs $50/g.
HandlingAs with other lanthanides, thulium has a low-to-moderate acute
toxic rating. It should be handled with care.