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It's Elemental

The Element Astatine

[Click for Isotope Data]


85 At Astatine 210

Atomic Number: 85

Atomic Weight: 210

Melting Point: 575 K (302°C or 576°F)

Boiling Point: Unknown

Density: about 7 grams per cubic centimeter

Phase at Room Temperature: Solid

Element Classification: Semi-metal

Period Number: 6

Group Number: 17

Group Name: Halogen

Special Notes: Radioactive

What's in a name? From the Greek word for unstable, astatos.

Say what? Astatine is pronounced as AS-teh-teen or as AS-teh-ten.

History and Uses:

Astatine was produced by Dale R. Carson, K.R. MacKenzie and Emilio Segrè by bombarding an isotope of bismuth, bismuth-209, with alpha particles that had been accelerated in a device called a cyclotron. This created astatine-211 and two free neutrons. This work was conducted at the University of California in 1940.

Small amounts of astatine exist in nature as a result of the decay of uranium and thorium, although the total amount of astatine in the earth's crust at any particular time is less than 30 grams. Due to its scarcity, astatine is produced when it is needed. A total of 0.05 micrograms (0.00000005 grams) of astatine have been produced to date.

Astatine's most stable isotope, astatine-210, has a half-life of 8.1 hours. It decays into bismuth-206 through alpha decay or into polonium-210 through electron capture.

Due to the small amounts produced and its short half-life, there are currently no uses for astatine outside of basic scientific research.

Estimated Crustal Abundance: Not Applicable

Estimated Oceanic Abundance: Not Applicable

Number of Stable Isotopes: 0 (View all isotope data)

Ionization Energy: 9.5 eV

Oxidation States: Unknown

Electron Shell Configuration:


2s2   2p6

3s2   3p6   3d10

4s2   4p6   4d10   4f14

5s2   5p6   5d10

6s2   6p5

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For questions about this page, please contact Steve Gagnon.