Thallium
Thallium (铊, symbol Tl) is chemical element number 81, a Post-Transition Metal in period 6, group 13 of the periodic table, with a standard atomic weight of about 204.38. Soft, malleable, highly toxic post-transition metal. Once used as rat poison.
Properties
| Atomic number | 81 |
|---|---|
| Symbol | Tl |
| Atomic mass | 204.38 u |
| Category | Post-Transition Metal |
| Period | 6 |
| Group | 13 |
| Electron configuration | [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p¹ |
| Electronegativity | 1.62 |
| Covalent radius | 145 pm |
| Density | 11.85 g/cm³ |
| Melting point | 577 K |
| Boiling point | 1746 K |
| Discovery | William Crookes, 1861 |
Overview
Soft, malleable, highly toxic post-transition metal. Once used as rat poison. Element 81, Thallium (Tl), is a Post-Transition Metal found in period 6, group 13. As a post-transition metal it is fairly soft with a low melting point, turning up in alloys, solders and coatings.
It has the configuration [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p¹ and an electronegativity near 1.62; its 3 outer-shell electrons drive its bonding. Under standard conditions it exists as a solid; it melts near 577 K (303.9 °C), boils near 1746 K (1472.9 °C), has a density around 11.85 g/cm³.
It is widely used in Electronics / Semiconductors and Research. On the safety side, it carries a high hazard rating. It was first described by William Crookes in 1861.
Electron shells
Electrons per shell: 2 · 8 · 18 · 32 · 18 · 3
Main uses
- Electronics / Semiconductors
- Research
Hazard
Compounds containing Thallium
No compounds in this knowledge base contain Thallium yet.
Data sources
Atomic mass uses IUPAC (CIAAW) standard atomic weights; the covalent radius is from Cordero et al. (2008). Verify on the RSC Periodic Table, PubChem and Wikipedia. Educational reference only.