Polonium
Polonium is a chemical element in the periodic table that has the symbol Po and atomic number 84. A rare radioactive metalloid, polonium is chemically similar to tellurium and bismuth and occurs in uranium ores. Polonium has been studied for possible use in heating spacecraft. It exists as a number of isotopes.When it is mixed or alloyed with beryllium, polonium can be a neutron source. Beryllium releases a neutron upon absorption of an alpha particle that is supplied by polonium-210. It has been used in this capacity as a neutron trigger for nuclear weapons. Other uses include:
Devices that eliminate static charges in textile mills and other places. However, beta sources are more commonly used and are less dangerous.
Brushes that remove accumulated dust from photographic films. The polonium used in these brushes is sealed and controlled thus minimizing radiation hazards.
As 210Po, a lightweight heat source to power thermoelectric cells.
History
Also called "Radium F", polonium was discovered by Marie Curie and her husband Pierre Curie in 1897 and was later named after Marie's homeland of Poland (Latin: Polonia). Poland at the time was under Russian, Prussian and Austrian domination, and not recognized as an independent country. It was Marie's hope that naming the element after her home land would add notoriety to its plight. Polonium may be the first element named to highlight a political controversy.
Polonium-210 was allegedly used to murder Alexander Litvinenko, a former Russian FSB counterintelligence officer, administered around November 1, 2006 with death occurring November 23, 2006. According to Pat Troop, chief executive of Britain's Health Protection Agency,[12] traces of polonium were found in Litvenenko's urine, as well as in several locations he had visited shortly before becoming ill.
This element was the first one discovered by the Curies while they were investigating the cause of pitchblende radioactivity. The pitchblende, after removal of uranium and radium, was more radioactive than both radium and uranium put together. This spurred them on to find the element. The electroscope showed it separating with bismuth.
Occurrence
A very rare element in nature, polonium is found in uranium ores at about 100 micrograms per metric ton (1:1010). Its natural abundance is approximately 0.2% of the abundance of radium.
In 1934 an experiment showed that when natural 209Bi is bombarded with neutrons, 210Bi, which is the parent of polonium, was created. Polonium may now be made in milligram amounts in this procedure which uses high neutron fluxes found in nuclear reactors. Only about 100 grams is believed to be produced each year, making polonium exceedingly rare.
Polonium has been found in tobacco smoke from tobacco leaves grown with phosphate fertilizers.