Astatine

//ˈæstəˌtin// noun

noun ·Rare ·Advanced level

Definitions

Noun
  1. 1
    A highly radioactive chemical element (symbol At), one of the halogens, with atomic number 85. countable, uncountable

    "Astatine, for instance, is practically unstudied. It has a name and a place on the periodic table (next to Marie Curie's polonium), but almost nothing else."

  2. 2
    a highly unstable radioactive element (the heaviest of the halogen series); a decay product of uranium and thorium wordnet

Synonyms

All synonyms
alabaminealabamineanglo helvetiumanglohelvetiumatatomic number 85

Example

More examples

"Fluorine, chlorine, bromine, iodine and astatine are halogens."

Etymology

From Ancient Greek ἄστατος (ástatos, “unstable”) + -ine.

Related phrases

eka-astatineatomic number

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Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.