Po is the chemical symbol for polonium, discovered by Marie Curie and named after Poland.
Marie Curie and Pierre Curie announced the discovery of polonium in 1898 while investigating the radioactivity of pitchblende. They named it after Poland, Marie Curie’s birthplace, which at that time was divided among neighboring empires and did not exist as an independent state.
Polonium has atomic number 84 and is a highly radioactive metalloid. It occurs naturally in trace amounts in uranium ores, where it forms during radioactive decay. Its isotopes are unstable, and polonium-210 is especially notable because it emits alpha particles.
The element has been used in specialized devices such as antistatic brushes and some heat sources for space equipment. Because polonium is intensely radioactive and toxic if ingested or inhaled, it is handled under strict controls. Its name is sometimes confused with palladium, whose symbol is Pd.