astatine
noun
- chemical element with the atomic number of 85
Wiktionary
Pronunciation: /ˈastətiːn/ / /ˈæstəˌtin/
noun
Etymology: From Ancient Greek ἄστατος (ástatos, “unstable”) + -ine.
- A highly radioactive chemical element (symbol At), one of the halogens, with atomic number 85.
“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.”