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For lasers. | Atomic Number: | 69 | Atomic Symbol: | Tm | | Atomic Weight: | 168.9342 | Electron Configuration: | 2-8-31-8-2 | | Shells: | 2,8,18,31,8,2 | Filling Orbital: | 4f13 | | 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
Cleve.
Occurence- Thulium occurs in small quantities along with other rare earths in a number
of minerals.
- It is obtained commercially from monazite, which contains about 0.007% of
the element.
- 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.
Properties- 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.
Uses- 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.
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