Which chemical element was originally known as Alabamine?

The story behind the answer

Astatine is correct because “Alabamine” was an early, ultimately incorrect name proposed in 1931 by researchers in Alabama who thought they had found element 85 and suggested the symbol Ab. Their claim didn’t hold up. The true discovery came in 1940 at UC Berkeley, where Corson, MacKenzie, and Segrè produced element 85 and named it astatine, from the Greek astatos, meaning “unstable.”

Astatine is a halogen and the rarest naturally occurring element on Earth—only tiny trace amounts form from uranium and thorium decay, and all its isotopes are radioactive. Memory tip: “Alabamine” = Alabama’s claim; later corrected to “Astatine,” the “unstable” halogen—A to A, but now firmly grounded in real evidence.