Astatine
⚕️ In Your World
Astatine is the rarest naturally occurring element in the Earth's crust, with less than 30 grams estimated to exist on the entire planet at any given time. It is intensely radioactive, and all its isotopes have very short half-lives. Because of its extreme rarity and instability, it has no commercial applications. However, some of its isotopes are being researched for use in targeted alpha-particle therapy for cancer treatment.
📖 The Discovery Story
Astatine's existence as the halogen below iodine was predicted by Dmitri Mendeleev. It was first successfully synthesized in 1940 by Dale R. Corson, Kenneth Ross MacKenzie, and Emilio Segrè at the University of California, Berkeley. They produced it by bombarding a target of bismuth-209 with alpha particles in a cyclotron. They named it "astatine" from the Greek word astatos, meaning "unstable," a fitting name for an element with no stable isotopes.
📊 Properties at a Glance
| Phase at STP | Solid (presumed) |
| Melting Point | 302 °C / 576 °F |
| Boiling Point | 337 °C / 639 °F |
| Electron Configuration | [Xe] 4f¹⁴5d¹⁰6s²6p⁵ |
| Abundance in Earth's Crust | Essentially zero |
⚠️ Safety & Handling
Astatine is intensely radioactive and poses an extreme radiological hazard. It is far more dangerous than polonium. Any visible amount would be instantly vaporized by the heat of its own radioactivity. It is only ever handled in microscopic, tracer quantities within specialized nuclear facilities, and its chemical properties are studied using these tiny amounts.