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.