Protactinium (pronounced /ˌproʊtækˈtɪniəm/, PROH-tak-TIN-ee-əm) is a chemical element with the symbol Pa and atomic number 91. Its longest-lived and most abundant naturally-occurring isotope by far, Pa-231, is a decay product of uranium-235 (U-235), and it has a half-life of 32,760 years. Much smaller trace amounts of shorter lived Pa-234 occur as decay products of uranium-238 (U-238).
Protactinium is a metallic element that belongs to the actino...
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Protactinium (pronounced /ˌproʊtækˈtɪniəm/, PROH-tak-TIN-ee-əm) is a chemical element with the symbol Pa and atomic number 91. Its longest-lived and most abundant naturally-occurring isotope by far, Pa-231, is a decay product of uranium-235 (U-235), and it has a half-life of 32,760 years. Much smaller trace amounts of shorter lived Pa-234 occur as decay products of uranium-238 (U-238).
Protactinium is a metallic element that belongs to the actinoid group, with a bright metallic luster that it retains for some time in contact with air. Protactinium is superconductive at temperatures below 1.4 K.
Due to its scarcity, high radioactivity, and high toxicity, there are currently no uses for protactinium outside of scientific research.
Protactinium-231 is formed by the alpha decay of U-235 followed by beta decay of thorium-231. The physicist Walter Seifritz once estimated that protactinium might possibly be used to build a nuclear weapon with a critical mass of 750±180 kg. This possibility ...
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