Polonium

Polonium is an extremely rare, intensely radioactive metal present in only trace amounts in the Earth's crust; it is produced artificially almost exclusively by irradiating bismuth-209 in nuclear reactors. Its best-known practical use exploits the heat released by alpha decay to build compact radioisotope heat sources for auxiliary heating on satellites and spacecraft. In industry, polonium-210 was once made into anti-static brushes used to neutralize the charge that builds up on photographic film, paper, and plastic film production lines: the alpha particles it emits ionize the air and thereby neutralize surface charge. Such applications have now dwindled sharply under strict radiation-handling regulations. Small quantities are still used as laboratory alpha sources and research tracers. Because of its extreme toxicity and the fact that polonium-210 has a half-life of only about 138 days, global consumption has always remained minimal.

Polonium compounds such as polonium dioxide (PoO2) and polonium tetrachloride (PoCl4) are prepared only in microgram amounts within nuclear chemistry laboratories, where they are used to study polonium's chemical behavior and separation flowsheets. They never enter any consumer product and have no large-scale industrial production.