| Astatine | ≡ |
| Symbol | At |
|---|---|
| Latin name | Astatum |
| Atomic number | 85 |
| Period | 6 |
| Element category | Halogens |
| Relative atomic mass | 209.9871 |
| Group | VII.A |
| Electronegativity | 2.2 |
| Oxidation numbers | -1, 1, 3, 5, 7 |
| State | Solid |
| Melting point [°C] | 302 |
| Boiling point [°C] | 330 |
| Atomic radius [pm] | 127 |
| Thermal conductivity [W m-1K-1] | 1.7 |
| Discovery | 1940 |
| 1.st ionization energy [eV] | 9.5 |
| Stable isotopes | 0 |
| Unstable isotopes | 21 |