Basic Information

Name: Thulium 
Symbol: Tm 
Atomic Number: 69 
Atomic Mass: 168.9342 amu 
Melting Point: 1545.0 °C (1818.15 K, 2813.0 °F) 
Boiling Point: 1727.0 °C (2000.15 K, 3140.6 °F) 
Number of Protons/Electrons: 69 
Number of Neutrons: 100 
Classification: Rare Earth 
Crystal Structure: Hexagonal 
Density @ 293 K: 9.321 g/cm3 
Color: silverish
Date of Discovery: 1879 
Discoverer: Per Theodor Cleve 
Name Origin: From Thule (ancient name of Scandinavia) 
Uses: power for portable x-ray machines 
Obtained From: gadolinite, euxenite, xenotime