Periodic Table of Elements

Element Protactinium - Pa

Comprehensive data on the chemical element Protactinium is provided on this page; including scores of properties, element names in many languages, most known nuclides of Protactinium. Common chemical compounds are also provided for many elements. In addition technical terms are linked to their definitions and the menu contains links to related articles that are a great aid in one's studies.

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Overview of Protactinium

Protactinium's Name in Other Languages

  • Latin: Protactinium
  • Czech: Protaktinium
  • Croatian: Protaktinij
  • French: Protactinium
  • German: Protaktinium - s
  • Italian: Protoattinio
  • Norwegian: Protactinium
  • Portuguese: Protactínio
  • Russian: Протактиний
  • Spanish: Protactínio
  • Swedish: Protaktinium

Atomic Structure of Protactinium

Chemical Properties of Protactinium

Physical Properties of Protactinium

Regulatory / Health

  • CAS Number
    • 7440-13-3
  • NFPA 704
    • Health:
    • Fire:
    • Reactivity:
    • Special Hazard: Radioactive<
    • OSHA Permissible Exposure Limit (PEL)
      • No limits set by OSHA
    • OSHA PEL Vacated 1989
      • No limits set by OSHA
    • NIOSH Recommended Exposure Limit (REL)
      • No limits set by NIOSH
    • Levels In Humans:
      Note: this data represents naturally occuring levels of elements in the typical human, it DOES NOT represent recommended daily allowances.
      • Blood/mg dm-3: nil
      • Bone/p.p.m: nil
      • Liver/p.p.m: nil
      • Muscle/p.p.m: nil
      • Daily Dietary Intake: nil
      • Total Mass In Avg. 70kg human: nil

    Who / Where / When / How

    • Discoverer: Kasimir Fajans and O.H. Göhring
    • Discovery Location: Karlsruhe Germany
    • Discovery Year: 1913
    • Name Origin:
      Greek: protos (first); its is the parent of actinium, which is formed by radioactive decay.
    • Abundance of Protactinium:
      • Earth's Crust/p.p.m.: N/A
      • Seawater/p.p.m.: 2E-11
      • Atmosphere/p.p.m.: N/A
      • Sun (Relative to H=1E12): N/A
    • Sources of Protactinium:
      Occurs in minute trace amounts in uranium ores such as pitchblende. Found among fission products of uranium, thorium, and plutonium. In 1961 the UK Atomic Energy Authority produced 125 g of pure protactinium from uranium fuel elements, which represents the major world stock of pratactinium.
    • Uses of Protactinium:
    • Additional Notes:
      Different sources credit the discovery of Protactinium because Kasimir Fajans and O.H. Göhring discovered Pa-231 in 1913, while Lise Meitner and Otto Hahn (Germany), K. Fajans (Germany) and F. Soddy, J.A. Cranston and A. Fleck (Scotland) discovered Pa-231 in 1917. We suspect that geo-political rivalries surrounding the First World War resulted in the 1913 discovery being omitted from many sources.

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