Return To Table

Tl

Thallium

81204.38
General Information
  • Melting Point: 577 K (304°C)
  • Boiling Point: 1746 K (1473°C)
  • Density: 11.850 g/cm3
  • Type of Substance: Post-Transition Metal
  • Discovered By: Sir William Crookes
  • Year of Discovery: 1861
Electrons and Ionisation
  • Electron Configuration: [Xe] 4f14 5d10 6s2 6p1
  • Electrons Per Shell: 2, 8, 18, 32, 18, 3
  • Oxidation States: 3, 2, 1, −1, −2, −5
  • Electronegativity: 1.62
History

Thallium was discovered spectroscopically in 1861 by Crookes. The element was named after the green spectral line, which identified the element (Greek "thallos", green twig). They had been expecting to isolate tellurium after removing selenium from the byproducts from a commercial sulphuric acid factory but instead found the new element thallium.

Engineering
  • Resistivity: 0.18  µΩ·m
  • Poisson Ratio: 0.45
  • Magnetism: Diamagnetic
  • Young's Modulus: 8 GPa
  • Shear Modulus: 2.8 GPa
  • Bulk Modulus: 43 GPa
  • Mohs Hardness: 1
  • Brinell Hardness: 26 - 5 MPa
  • Thermal Expansion: 29.9×10-6 K-1
  • Thermal Conductivity: 46.1 W/m·K