Pa Protactinium     Atomic number : 91 
    Relative atomic mass (12C = 12.0000) :  231.03588 
    P H Y S I C A L     D A T A
Group 3 actinide
 
Density / kg m-3 :  15 370 (est.)
 
Melting point / K :  2113 
 
Boiling point / K :  c. 4300
 
    D I S C O V E R Y
Protactinium was discovered in 1913 by Kasimir Fajans and O.H. Göhring as the short lived isotope 234Pa. Isotope 231Pa was discovered in 1917 by Lise Meitner and Otto Hahn at Berlin (Germany), K. Fajans at Karlsruhe (Germany) and by F. Soddy, J.A. Cranston and A. Fleck at Glasgow, Scotland.
 
    G E O L O G I C A L     D A T A
Abundances
 
Sun (relative to H = 1 × 1012) : n.a.
 
Earth's crust / p.p.m. : traces
 
Oxidation state : V
 
  
 
Seawater / p.p.m. : 2 × 10-11
    B I O L O G I C A L     D A T A
Level in humans
 
Organs: nil
 
  
 
Daily dietary intake : nil
 
Total mass of element
in average (70 kg) person :
nil

 

NetElements II  

A portrait of protactinium is available on the Visual Elements site. Up to 200 individual items of information on this element are available in The Elements.


Text copyright John Emsley 1999.   HTML and page layout copyright Simon Hall 1999.
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NetElements II last modified October 27th, 1999