Polonium
Element 84 · Post-Transition Metal
Polonium was the first element discovered through its radioactivity, isolated by Marie and Pierre Curie in 1898 and named for Marie's native Poland. Every isotope is radioactive, and its intense alpha emission makes even microgram samples dangerously hot — a capsule of it glows blue from the excited air around it.
Because of that energy, polonium has powered static eliminators and the heaters of space probes, and mixed with beryllium it becomes a neutron source. It has no safe consumer use and is produced only in nuclear reactors under strict controls.
Key facts
| Atomic number | 84 |
|---|---|
| Atomic weight | [209] |
| Category | Post-Transition Metal |
| Group / Period | 16 / 6 |
| Block | p |
| Electron configuration | 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p4 |
| Common oxidation states | +4, +2 |
| State at STP | Solid |
| Electronegativity | 2.00 |
| Density | 9.20 g/cm³ |
| Melting point | 254 °C |
| Boiling point | 962 °C |
Occurrence
Only traces of polonium exist in uranium ores. Usable amounts are made by irradiating bismuth in nuclear reactors.
Applications
Static eliminators for industry
Space probe heaters (RTGs)
Neutron sources (with beryllium)
Research sources
Common compounds
- polonium dioxide
- polonium hydride
Polonium was the first element discovered through its radioactivity, and Marie Curie named it after her native Poland.
Data source: IUPAC standard atomic weights 2021