Crossword clue: a short-lived radioactive metallic element formed from uranium and disintegrating into actinium and then into lead

The most common answer is protactinium (12 letters).

1 answer found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

Possible answers

protactinium 12 letters wn-def

a short-lived radioactive metallic element formed from uranium and disintegrating into actinium and then into lead