protactinium
Sign in to saveProtactinium is a chemical element; it has symbol Pa and atomic number 91. It is a dense, radioactive, silvery-gray actinide metal which readily reacts with oxygen, water vapor, and inorganic acids. It forms various chemical compounds, in which protactinium is usually present in the oxidation state +5, but it can also assume +4 and even +3 or +2 states. Concentrations of protactinium in the Earth's crust are typically a few parts per trillion, but may reach up to a few parts per million in some uraninite ore deposits. Because of its scarcity, high radioactivity, and high toxicity, there are cu
AI overview
Protactinium is a rare, radioactive metal element (symbol Pa) that is dense, silvery-gray, and highly reactive with oxygen and water. Because it is extremely scarce in nature, highly radioactive, and toxic, it has limited practical applications and requires careful handling.
AI-generated from the Wikipedia summary — may contain errors.
Article
18 sectionsContents
- History
- Nuclear fission
- Occurrence
- In nuclear reactors
- Preparation
- Properties
- Chemical compounds
- Oxides and oxygen-containing salts
- Halides
- Other inorganic compounds
- Organometallic compounds
- Applications
- Precautions
- See also
- Notes
- References
- Bibliography
- External links
Protactinium is a chemical element; it has symbol Pa and atomic number 91. It is a dense, radioactive, silvery-gray actinide metal which readily reacts with oxygen, water vapor, and inorganic acids. It forms various chemical compounds, in which protactinium is usually present in the oxidation state +5, but it can also assume +4 and even +3 or +2 states. Concentrations of protactinium in the Earth's crust are typically a few parts per trillion, but may reach up to a few parts per million in some uraninite ore deposits. Because of its scarcity, high radioactivity, and high toxicity, there are currently no uses for protactinium outside scientific research, and for this purpose, protactinium is mostly extracted from spent nuclear fuel.
The element was first identified in 1913 by Kazimierz Fajans and Oswald Helmuth Göhring and named "brevium" because of the short half-life of the specific isotope studied, 234mPa. A more stable isotope of protactinium, 231Pa, was discovered in 1917/18 by Lise Meitner in collaboration with Otto Hahn, and they named the element protactinium. In 1949, the IUPAC chose the name "protactinium" and confirmed Hahn and Meitner as its discoverers. The new name meant "(nuclear) precursor of actinium," suggesting that actinium is a product of radioactive decay of protactinium. John Arnold Cranston (working with Frederick Soddy and Ada Hitchins) is also credited with discovering the most stable isotope in 1915, but he delayed his announcement due to being called for service in the First World War.