Other meanings of Polonium
Chemistry
Polonium is a rare and highly radioactive chemical element with the symbol Po and atomic number 84. Discovered by Marie and Pierre Curie in 1898, it was named after Poland, Marie Curie's homeland. Polonium is a metalloid with no stable isotopes, and its most common isotope, polonium-210, has a half-life of 138 days. It is primarily used in industrial anti-static devices and as a heat source in space applications, but it is also infamous for its use in the 2006 poisoning of Alexander Litvinenko.
Polonium was the first element discovered by Marie and Pierre Curie in 1898 while they were investigating the radioactivity of pitchblende, a uranium ore. They isolated it chemically from bismuth fractions, and it was named after Marie Curie's native Poland. Polonium is a silvery-gray metalloid that is chemically similar to tellurium and bismuth. It has 33 known isotopes, all radioactive, with polonium-210 being the most widely studied. Its intense radioactivity causes it to glow blue in the dark, and it readily emits alpha particles, which are stopped by a sheet of paper but are hazardous if ingested or inhaled.
Polonium-210 is used in small amounts in anti-static brushes to eliminate static electricity in industrial processes, such as in textile manufacturing and photographic film production. It is also used as a heat source in radioisotope thermoelectric generators (RTGs) for space probes, notably in the Soviet-era Luna missions, where it provided warmth for instruments. In the medical field, polonium has been used in research on radiation therapy, though its use is limited due to its high toxicity. The element's alpha emissions are also employed in neutron sources when mixed with beryllium.
Polonium is extremely toxic, with a lethal dose of polonium-210 estimated to be as little as 0.1 micrograms if ingested. Its alpha particles are highly ionizing, causing severe damage to biological tissues, and it is a known carcinogen. The most notorious incident involving polonium was the 2006 poisoning of former Russian spy Alexander Litvinenko, who died after consuming tea laced with polonium-210. Occupational exposure is regulated by agencies such as the U.S. Environmental Protection Agency, which sets strict limits on permissible levels in the environment. Because polonium is a natural decay product of uranium, it is present in trace amounts in soil and tobacco, contributing to the carcinogenic effects of smoking.
Polonium was used in early atomic bomb research: the 'Urchin' initiator in the first nuclear weapons used polonium-210 and beryllium to generate neutrons. The element is also a significant source of background radiation in the human body, though in minuscule amounts. In 1943, polonium was produced in quantity at the Oak Ridge National Laboratory as part of the Manhattan Project. Polonium-210 has been used in scientific studies of alpha-particle effects on materials, and it has been proposed as a power source for lunar missions. Additionally, polonium's high volatility means it can easily become airborne, making it a hazard in laboratory settings. Its chemistry is still not fully understood due to its intense radioactivity, which complicates experimental study.
Polonium is one of the rarest elements in the Earth's crust, with an abundance of about 1 part per 10^15.
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