Protactinium (Pa)
Protactinium: The Radioactive Progenitor
Protactinium is a silvery, highly radioactive metal. Its name comes from the Greek words protos (“first” or “parent”) and actinium, because it decays into the element actinium. It is extremely rare and very toxic due to its strong radioactivity, so it is used only for scientific research.
A Brief History of Protactinium
The possibility of an element between thorium and uranium was predicted by Dmitri Mendeleev, but it wasn’t confirmed until decades later.
1913: German scientists Kasimir Fajans and Otto Göhring identified a short-lived isotope of the element. They named it brevium because of its very short half-life.
1918: A longer-lived isotope, protactinium-231 (half-life: 32,500 years), was isolated from uranium ore in Berlin by Lise Meitner and her team, securing the element’s place on the periodic table.
1934: Aristid von Grosse succeeded in producing the first sample of pure protactinium metal.
Natural Abundance & Biological Role
Protactinium occurs in tiny amounts in nature, usually within uranium ores as part of radioactive decay chains. It can also be extracted from spent nuclear fuel rods.
Protactinium has no biological role. Its extreme radioactivity makes it highly toxic and dangerous to handle.