Less than 30 grams on the entire planet — and that's not a joke. Astatine is so rare that no human has ever seen it with the naked eye. It appears from the decay of uranium and thorium, then vanishes faster than you can blink. Its longest half-life is just 8.1 hours.
Astatine is the last natural halogen in the periodic table. It should resemble iodine, but it's far more 'metallic' than its siblings. Scientists create it on cyclotrons by bombarding bismuth with alpha particles. And despite its scarcity, astatine-211 may become a real weapon against cancer.
Astatine was first synthesized in 1940 at the University of California, Berkeley. Scientists Dale Corson, Kenneth MacKenzie, and Emilio Segre fired alpha particles at bismuth in a cyclotron and produced a few atoms of a new element. They named it from the Greek 'astatos' — unstable. A perfect fit: every isotope decays within hours.
Today, astatine-211 is a rising star in nuclear medicine. Its alpha particles destroy cancer cells while sparing healthy tissue. Clinical trials are already underway in several countries.
Astatine is extremely radioactive. Its alpha radiation destroys cells on the slightest contact. Like iodine, astatine accumulates in the thyroid gland, making it particularly dangerous. All work is conducted only with microscopic quantities in sealed gloveboxes with remote manipulation. Lead shielding and continuous radiation monitoring are mandatory.
Less than 30 grams of astatine exist in the entire Earth's crust at any moment. It's the rarest naturally occurring element — billions of times rarer than gold.
The most stable astatine isotope (At-210) 'lives' for just 8.1 hours. Within a day, almost nothing remains.
The name 'astatine' comes from the Greek word 'astatos' — unstable. No other element so honestly warns you about its own nature.
Astatine-211 is oncology's hope. Its alpha particles travel only a few cell widths, destroying tumors with pinpoint accuracy without damaging surrounding tissue.
No human has ever seen astatine with the naked eye. All experiments use just a few million atoms — completely invisible to us.
Astatine was discovered in 1940 — the last natural halogen found. But Mendeleev predicted its existence back in 1869, calling it 'eka-iodine.'
| Isotope | Mass (u) | Abundance | Half-life | Decay |
|---|---|---|---|---|
210At☢ | 209.987148 | synthetic | 8.1 hours | EC/α |
211At☢ | 210.987496 | synthetic | 7.214 hours | EC/α |
Cyclotron bombardment of bismuth