About Element Astatine - WorldOfChemicals

Astatine-Element information, properties, uses and facts


Astatine is a chemical compound with symbol At and atomic number 85, which is a radioactive element. Astatine is named after a Greek word astatos, meaning unstable. It is the member of block p and period 6 of the periodic table and it belongs to halogens family. It is one among the rarest naturally found on the earth. Even after decades of discovery, research only little has been known about astatine. Astatine was discovered in 1940 by scientists Dale Corson, Kenneth McKenzie and Emilio Segre.

Astatine Properties

Astatine breaks down very soon, thus not allowing much experimentation. Therefore very less properties are known till date for astatine.

  • Melting point: 302 degree Celsius, boiling point: 337 degree Celsius.

  • Astatine is highly toxic because of its high radioactivity.

  • Electronegativity according to Pauling: 2.2, its phase at STP is solid.

  • Mass number of astatine is 210, which is the most stable isotope of astatine.

  • It has covalent radius of 150pm and Van der Waals radius of 202pm.

  • Astatine can react with hydrogen forming hydrogen astatide, which then forms hydroastatic acid when dissolved in water.

  • Astatine forms complexes with a metal chelating agent, EDTA.

  • Most of the isotopes of astatine are very unstable with one second or less half-lives.

  • Astatine is known to bind with boron, carbon and nitrogen. In benzene, astatine can replace atom of hydrogen, forming astatobenzene (C6H5At), and then this can be oxidized by chlorine to C6H5AtCl2.

Astatine Uses

Astatine has an important role in nuclear medicine. Astatine 211 is used for cancer treatment and as a radiotherapy only sometimes. Astatine is accumulated in the thyroid gland and liver in the similar way iodine is accumulated, but astatine does not emit electrons with high energy like iodine.

Astatine interesting facts

  • Astatine have 32 isotopes, all astatine isotopes are radioactive, means all breakdowns easily and get transformed into other elements.

  • Up to only 25 grams of astatine, which is naturally existing can be found at a point of time on earth.

  • Being highly radioactive yet nearly does not possess any health or environmental effects due to its very sort half-lives and rarity of presence.

  • Most of the properties of astatine are still not known, like its color. It is believed that astatine is dark, close to black in appearance based on the other halogen family members color patterns.

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