Astatine

Notable Characteristics This highly radioactive element has been confirmed by mass spectrometers to behave chemically much like other halogens, especially iodine (it probably accumulates in the thyroid gland like iodine). Astatine is thought to be more metallic than iodine. Researchers at the Brookhaven National Laboratory have performed experiments that have identified and measured elementary reactions that involve astatine.

The total amount of astatine in the earth's crust is estimated to be less than 1 oz (28 g) at any one time. History Astatine (Greek astatos meaning "unstable") was first synthesized in 1940 by Dale Corson, K.R. MacKenzie, and Emilio Segre of the University of California by barraging bismuth with alpha particles. Occurrence Astatine is produced by bombarding bismuth with energetic alpha particles to obtain relatively long-lived At-209 - At-211, which can then be distilled from the target by heating in the presence of air. Isotopes Astatine has about 20 known isotopes, all of which are radioactive; the longest-lived isotope is ²¹⁰At which has a half-life of only 8.3 hours. Astatine is a halogen and possibly accumulates in the thyroid like iodine.

External Links

• WebElements.com - Astatine (http://www.webelements.com/webelements/elements/text/At/index)
• EnvironmentalChemistry.com - Astatine (http://environmentalchemistry.com/yogi/periodic/At)