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Protactinium

Rare, radioactive actinide metal with no uses outside research.

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It is one of the rarest and most expensive naturally occurring elements, with concentrations in the Earth's crust typically a few parts per trillion.[1][2] Protactinium, with atomic number 91 and symbol Pa, is a silvery-gray metal belonging to the actinide series, characterized by its high density, radioactivity, and strong reactivity with oxygen, water vapor, and inorganic acids.[1] The element's extreme rarity, intense radioactivity, and high toxicity mean its only current applications are in fundamental scientific work, with most supplies coming from reprocessed spent nuclear fuel.[1]

Quick Facts

Atomic number
91
Discovered by
  • Kazimierz Fajans and Oswald Helmuth Göhring (1913)
  • Lise Meitner and Otto Hahn (1917/18)
  • John Arnold Cranston (1915)
Most stable isotope
231Pa
Natural occurrence
From decay of uranium-235

Facts from the source article.

Key facts and history

In 1871, Dmitri Mendeleev predicted the existence of an element between thorium and uranium, leaving the space below tantalum in group V empty.[3] In 1961, the United Kingdom Atomic Energy Authority produced 127 grams of 99.9% pure protactinium-231 by processing 60 tonnes of waste material.[4] In 1913, Kazimierz Fajans and Oswald Helmuth Göhring first identified the element while studying uranium-238 decay chains, naming their discovery "brevium" due to the 1.16-minute half-life of the isotope 234m Pa they had found.[5][6][7] John Arnold Cranston, collaborating with Frederick Soddy and Ada Hitchins, is also recognized for discovering the most stable isotope in 1915, though he withheld his announcement after being called up for service in the First World War.[8]

What the research sources say

The Los Alamos National Laboratory account states that protactinium is a very rare, dense, silvery-gray metal.[9] Protactinium occurs naturally in very small amounts in all uranium ores, especially pitchblende.[9] The Los Alamos National Laboratory notes that protactinium has 29 isotopes whose half-lives are known, with mass numbers 211 to 239.[9] That source also reports that nearly all naturally occurring protactinium is protactinium-231, approximately 99.9999%.[9]

The Los Alamos National Laboratory account confirms that one isotope, protactinium-231, can be combined with thorium-230 and used to date marine sediments.[9]

References

  1. Wikipedia, "Protactinium" (CC BY-SA 4.0), which cites: bismuth is the other, which has been shown to have a half life of over 10^18 years (original not read by us) en.wikipedia.org
  2. Wikipedia, "Protactinium" (CC BY-SA 4.0), which cites: Protactinium , Argonne National Laboratory, Human Health Fact Sheet, August 2005 (original not read by us) en.wikipedia.org
  3. Wikipedia, "Protactinium" (CC BY-SA 4.0), which cites: Emsley, "Nature's Building Blocks: An A-Z Guide to the Elements", Oxford University Press, 2003, p. 347–349 (we also read that source) en.wikipedia.org
  4. Wikipedia, "Protactinium" (CC BY-SA 4.0), which cites: Hammond, C. R., "The Elements, in Handbook of Chemistry and Physics", CRC press, 2004-06-29; Myasoedov, "The Chemistry of the Actinide and Transactinide Elements", Springer, 2006; Emsley, "Nature's Building Blocks: An A-Z Guide to the Elements", Oxford University Press, 2003, p. 347–349; "Periodic Table of Elements: Protactinium", Los Alamos National Laboratory (we also read that source) en.wikipedia.org
  5. Wikipedia, "Protactinium" (CC BY-SA 4.0), which cites: Meitner, "Die Muttersubstanz des Actiniums, Ein Neues Radioaktives Element von Langer Lebensdauer", Zeitschrift für Elektrochemie und angewandte physikalische Chemie, 1918, p. 169–173 (original not read by us) en.wikipedia.org
  6. Wikipedia, "Protactinium" (CC BY-SA 4.0), which cites: Johansson, "Decay of UX1, UX2, and UZ", Physical Review, 1954, p. 1075–1080 (original not read by us) en.wikipedia.org
  7. Wikipedia, "Protactinium" (CC BY-SA 4.0), which cites: Greenwood, p. 1250; Greenwood, p. 1254; Fajans, K., "Über die komplexe Natur des Ur X", Naturwissenschaften, 1913, p. 339; Fajans, K., "Über das Uran X<sub>2</sub>-das neue Element der Uranreihe", Physikalische Zeitschrift, 1913, p. 877–84; Eric Scerri, A tale of seven elements, (Oxford University Press 2013) , p.67–74; Fajans, "Discovery and Naming of the Isotopes of Element 91", Nature, 1973, p. 137–138; Meitner, "Die Muttersubstanz des Actiniums, Ein Neues Radioaktives Element von Langer Lebensdauer", Zeitschrift für Elektrochemie und a en.wikipedia.org
  8. Wikipedia, "Protactinium" (CC BY-SA 4.0), which cites: John Arnold Cranston . University of Glasgow (original not read by us) en.wikipedia.org
  9. "Periodic Table of Elements: Protactinium", Los Alamos National Laboratory. facts only, no text reused. periodic.lanl.gov

Each numbered sentence above was checked against the source it cites before publication. Sentences citing Wikipedia adapt text from the English Wikipedia article Protactinium (contributors), used under CC BY-SA 4.0; this entry is available under the same licence. Other sources were used for facts only; no text or images are copied from them.

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Protactinium · Chemical Elements & Metals

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Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.

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