astatine

American  

[as-tuh-teen, -tin] / ˈæs təˌtin, -tɪn /

noun

Chemistry.

1. a rare element of the halogen family. At; 85.

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astatine British  

/ -tɪn, ˈæstəˌtiːn /

noun

1. a radioactive element of the halogen series: a decay product of uranium and thorium that occurs naturally in minute amounts and is artificially produced by bombarding bismuth with alpha particles. Symbol: At; atomic no: 85; half-life of most stable isotope, ²¹⁰ At: 8.1 hours; probable valency: 1,3,5, or 7; melting pt: 302°C; boiling pt: 337°C (est)

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astatine Scientific  

/ ăs′tə-tēn′ /

1. A highly unstable, rare, radioactive element that is the heaviest of the halogen elements. Its most stable isotope has a half-life of 8.3 hours. Atomic number 85; melting point 302°C; boiling point 337°C; valence probably 1, 3, 5, 7.

2. See Periodic Table

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Etymology

Origin of astatine

1945–50; < Greek ástat ( os ) not steadfast, unstable ( astatic ) + -ine ²

Example Sentences

"We are one of a handful of U.S. centers capable of routinely producing astatine in medically relevant quantities and delivering it to nearby facilities."

From Science Daily

There are no stable isotopes of astatine; all decay with half-lives in the order of hours at the most, seconds to minutes for the most part.

From Nature

In 1943, three years after astatine was first synthesized artificially in a nuclear reactor, it was discovered that the element occurs naturally in miniscule amounts in the earth’s crust.

From Scientific American

This element, the second-heaviest ever created, is a homologue of astatine, meaning that it sits right below astatine on the periodic table and likely shares similar properties.

From Scientific American

Americans were generally absent from the race until well into the twentieth century, and it was not until 1940 that the first American-discovered element, astatine, was announced by a team at Berkeley.

From Forbes