astatine

[ as-tuh-teen, -tin ]

noun

, Chemistry.

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

astatine

/ -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, ²¹⁰At: 8.1 hours; probable valency: 1,3,5, or 7; melting pt: 302°C; boiling pt: 337°C (est)

astatine

/ 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

Word History and Origins

Origin of astatine¹

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

Word History and Origins

Origin of astatine¹

C20: from Greek astatos unstable (see astatic ) + -ine ²

Example Sentences

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

The astatine nightmares wake me, sweating, from sleep, linger briefly and disperse in the morning light.

From Nature

I don’t know what the astatine nightmares are.

From Nature

Some astatine isotopes undergo alpha decay.

From Nature

Like the element above it in the periodic table, iodine, astatine has a tendency to be metabolized in the thyroid gland and could therefore be used to monitor medical conditions involving the thyroid and the throat area in general.

From Scientific American