Thulium
Name: Thulium
Symbol: Tm
Atomic Number: 69
Mass fraction of the earth’s shell: 2 x 10 -5 ppm
Melting Point: 1545°C
Boiling Point: 1947 °C
Electrical Conductivity: 1,47 x 106 A·V−1·m−1
Name: Thulium
Symbol: Tm
Atomic Number: 69
Mass fraction of the earth’s shell: 2 x 10 -5 ppm
Melting Point: 1545°C
Boiling Point: 1947 °C
Electrical Conductivity: 1,47 x 106 A·V−1·m−1
HISTORY
CHARACTERISTICS & EXTRACTION
The base, very soft heavy metal, shimmers silvery-white. It is stable in dry air but must be protected from moisture. Thulium is electropositive and a strong reducing agent. Humid air causes it to tarnish, and thulium dissolves in water.
Thulium removed from nuclear reactors serves as a source of X-ray radiation.
In nature, thulium is mostly found in combination with yttrium and the heavy lanthanides. Monazite sand is needed for its production. First, it is separated from the other rare earth metals by ion exchange. It is then obtained by metallothermic reduction of the trifluoride with calcium, magnesium, or potassium. The use of thulium is limited because there are only a manageable number of commercial applications. One of these is TV sets: here, thulium activates the phosphors on the screen surface