Protactinium
⚛️ In Your World
Protactinium is a dense, silvery-gray radioactive metal that is one of the rarest and most expensive naturally occurring elements. It has no commercial uses due to its scarcity, high radioactivity, and toxicity. Its primary importance is in basic scientific research, particularly in understanding the complex chemistry of the actinides.
📖 The Discovery Story
The existence of an element between thorium and uranium was predicted by Dmitri Mendeleev in 1871. An isotope of protactinium was first identified in 1913 by Kasimir Fajans and Oswald Helmuth Göhring, who named it "brevium" due to its short half-life. The more stable isotope, protactinium-231, was discovered in 1917 by Lise Meitner and Otto Hahn, and independently by Frederick Soddy and John Cranston. The name was changed to "protactinium" in 1949, from the Greek protos (first) and actinium, as it is the "parent" or precursor of actinium in its decay chain.
📊 Properties at a Glance
| Phase at STP | Solid |
| Melting Point | 1572 °C / 2862 °F |
| Boiling Point | 4027 °C / 7280 °F (estimated) |
| Electron Configuration | [Rn] 5f²6d¹7s² |
| Abundance in Earth's Crust | Trace amounts |
⚠️ Safety & Handling
Protactinium is both highly radioactive and toxic, posing a severe radiological hazard. It requires the same stringent precautions as plutonium. It must only be handled in a specialized glove box within a nuclear facility to prevent any chance of inhalation or ingestion, which would be extremely dangerous.