Astatine
Astatine (砹, symbol At) is chemical element number 85, a Halogen in period 6, group 17 of the periodic table, with a standard atomic weight of about 210. Rarest naturally occurring element. All isotopes are radioactive.
Properties
| Atomic number | 85 |
|---|---|
| Symbol | At |
| Atomic mass | 210 u |
| Category | Halogen |
| Period | 6 |
| Group | 17 |
| Electron configuration | [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁵ |
| Electronegativity | 2.2 |
| Covalent radius | 150 pm |
| Density | 7 g/cm³ |
| Melting point | 575 K |
| Boiling point | 610 K |
| Discovery | Corson, MacKenzie, Segrè, 1940 |
Overview
Rarest naturally occurring element. All isotopes are radioactive. Element 85, Astatine (At), is a Halogen found in period 6, group 17. As a halogen it is a reactive nonmetal that readily gains one electron to form a −1 ion.
With 7 electrons in its outermost shell, Astatine bonds accordingly; full configuration [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁵, electronegativity 2.2. At room temperature it is normally a solid; it melts near 575 K (301.9 °C), boils near 610 K (336.9 °C), has a density around 7 g/cm³.
Common applications range across Medical / Pharma and Research. On the safety side, it carries a high hazard rating. It was first described by Corson, MacKenzie, Segrè in 1940. Browse elements of the same category in the browse view.
Electron shells
Electrons per shell: 2 · 8 · 18 · 32 · 18 · 7
Main uses
- Medical / Pharma
- Research
Hazard
Compounds containing Astatine
No compounds in this knowledge base contain Astatine 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.