Information valid for Tm-169 unless otherwise noted

Thulium

Basic Information

Symbol: Tm
Atomic Number: 69
Mass: 168.9342
Melting Point: 1545.0 C
Boiling Point: 1727.0 C
Number of Protons/Electrons: 69
Number of Neutrons: 100
Classification: Rare Earth
Crystal Structure: Hexagonal
Density @ 293 K: 9.321 g/cm³
Color: silverish

Atomic Structure

Number of Energy Levels: 6 First Energy Level: 2 Second Energy Level: 8 Third Energy Level: 18 Fourth Energy Level: 31 Fifth Energy Level: 8 Sixth Energy Level: 2

Isotopes

Facts

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