Key information
Atomic number: 
81
Atomic weight: 
204.37
Density: 
11850 kg/m³
Boiling point: 
1730.16° K
Melting point: 
576.16° K
Heat vapour: 
162.48 kJ/mol
Heat fusion: 
4.27 kJ/mol
Thermal conductivity: 
5.5 W/m/K
Specific heat capacity: 
38.94 J/kg/K

The chemical symbol for Thallium is Tl. When freshly exposed to air, thallium exhibits a metallic lustre, but soon develops a bluish-grey tinge, resembling lead in appearance.

Amazon Books
Image of The Last Sorcerers: The Path from Alchemy to the Periodic Table
Author: National Academy of Sciences, Richard Morris
Publisher: Henry (Joseph) Press (2003)
Binding: Hardcover, 294 pages