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- Name : Thulium
- Symbol : Tm
- Atomic # : 69
- Atom weight: 168.934
- Melting P. : 1545
- Boiling P. : 1950
- Oxidation : +3
- Pronounced : THOO-li-em
- From : Named for Thule, the ancient name for Scandinavia
- Identified : Per Theodor Cleve in 1879
- Appearance : Soft, malleable, ductile, silvery metal
- Note : Least abundant of the naturally occurring rare earths
-
- [Properties]
-
- Thulium is near the end of the lanthanum series of elements. Elements in
- this part of the periodic chart are all metals. All are heavy, and most are
- lustrous and silvery gray in color. Thulium is especially soft for a
- lanthanide. It can be easily cut with a knife.
- The melting temperature of thulium is so high that it poses special
- problems in operations that require forcing a metal to its molten state.
- For one thing, any container for molten thulium is affected by the high
- temperature and inevitably adds some impurities to the thulium. The vapor
- pressure is also so high that large amounts tend to evaporate away from the
- sample at atmospheric gas pressures.
-