Stable isotope Thulium (Tm)

Isotope Z(p) N(n) Atomic Mass Natural Abundance Nuclear Spin
Tm-169 69 100 168.934211 100.00% 1/2+

Properties of Thulium

Name Thulium
Symbol Tm
Atomic number 69
Atomic weight 168.9342
Standard state Solid at 298 ºK
CAS Registry ID 7440-30-4
Group in periodic table N/A
Group name Lanthanoid
Period in periodic table 6 (Lanthanoid)
Block in periodic table f-block
Color Silvery white
Classification Metallic
Melting point 1545 °C
Boiling point 1947 °C
Vaporization point 1947 °C
Thermal conductivity 16.9 W/(m·K) at 298.2 ºK
Electrical resistivity 79.0 µΩ·cm at 25 ºC
Electronegativity 1.2
Specific heat 0.16 kJ/kg K
Heat of vaporization 250 kJ·mol-1
Heat of fusion 16.8 kJ·mol-1
Density of liquid 8.56 g/cm3 at 1545 °C
Density of solid 9.32 g/cm3
Electron configuration [Xe]4f136s2
Atomic radius 1.73 Å
Ionic radius Tm3+: 1.09 Å (coordination number 7)
Oxidation states +2, +3
Most stable oxidation state +3