astatine

Definition

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

Etymology

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

Example Sentences

• "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."