Stable isotope Thallium (Tl)

 
Isotope Z(p) N(n) Atomic Mass Natural Abundance Enrichment Level Chemical Form
Tl-203 81 122 202.972329 29.52% >99.00% Metal
Tl-203 81 122 202.972329 29.52% >99.00% Oxide
Tl-205 81 124 204.974412 70.48% 99.90% Metal
Tl-205 81 124 204.974412 70.48% 99.90% Oxide

Properties of Thallium

Name Thallium
Symbol Tl
Atomic number 81
Atomic weight 204.38
Standard state Solid at 298 ºK
CAS Registry ID 7440-28-0
Group in periodic table 13
Group name None
Period in periodic table 6
Block in periodic table p-block
Color Silvery white
Classification Metallic
Melting point 303.5 °C
Boiling point 1457 °C
Vaporization point 1473 ºC
Thermal conductivity 46.1 W/(m·K) at 298.2 °K
Electrical resistivity 18.0 µΩ·cm at 0 °C
Electronegativity 1.8
Specific heat 0.13 kJ/kg K
Heat of vaporization 165 kJ·mol-1
Heat of fusion 4.2 kJ·mol-1
Density of liquid 11.22 g/cm3
Density of solid 11.85 g/cm3
Electron configuration [Xe]4f145d106s26p1
Atomic radius 1.70 Å
Oxidation states +1 (thallous), +3 (thallic)