Found 2 items, similar to protactinium.
English → English (WordNet) Definition: protactinium protactinium n : a short-lived radioactive metallic element formed from uranium and disintegrating into actinium and then into lead [syn: protoactinium, Pa, atomic number 91]
English → English (gcide) Definition: Protactinium Protactinium \Protactinium\ The radioactive chemical element, of atomic number 91; Atomic symbol Pa; at. wt. of longest-lived isotope, 231 (T1/2 = 32,500 yrs.) Also called brevium, Uranium X2 and UX2. [PJC]