Tl
Thallium Symbol (Tl)
Thallium is element 81 of the periodic table. Copy its symbol Tl and see its atomic weight, electron configuration and physical properties.
What does Tl mean?
Tl is the chemical symbol for thallium, element number 81 in the periodic table. Thallium is a post-transition metal in group 13, period 6. It is a solid at room temperature and was discovered in 1861.
Codes and properties
| Chemical symbol | Tl |
|---|---|
| Atomic number (Z) | 81 |
| Atomic weight (PubChem) | 204.383 |
| Group / period | 13 / 6 |
| Element category | post-transition metal |
| Electron configuration | [Xe]6s² 4f¹⁴ 5d¹⁰ 6p¹ |
| State at 20 °C | Solid |
| Oxidation states | +3, +1 |
| Electronegativity (Pauling) | 1.62 |
| Melting point | 577 K (303.85 °C) |
| Boiling point | 1746 K (1472.85 °C) |
| Density | 11.8 g/cm³ |
| Discovered | 1861 |
How to type Tl
- Plain text: type
Tl— element symbols are ordinary Latin letters, with the first letter capitalised and the second lowercase. - Subscripts in formulas: use Unicode subscript digits (₀₁₂₃₄₅₆₇₈₉) for formulas such as H₂O — copy them from the chemistry keyboard.
- LaTeX: write
\mathrm{Tl}in math mode, or use the mhchem package:\ce{Tl}. - HTML:
Tl; for subscripts use<sub>, e.g.H<sub>2</sub>O.
Frequently asked questions
What is the chemical symbol for thallium?
The chemical symbol for thallium is Tl.
What is the atomic number of thallium?
Thallium has atomic number 81, meaning each atom has 81 protons.
What is the electron configuration of thallium?
The ground-state electron configuration of thallium is [Xe]6s² 4f¹⁴ 5d¹⁰ 6p¹.
Related symbols
Keep exploring
Reference: Thallium on PubChem (NIH)