A single gram of 210Po generates 140 watts of power. A few curies (1 curie equals 37 gigabecquerels) of 210Po emit a blue glow which is caused by excitation of surrounding air. A milligram of 210Po emits about as many alpha particles per second as 4.5 grams of 226Ra. 209Po (half-life 103 years) and 208Po (half-life 2.9 years) can be made through the alpha, proton, or deuteron bombardment of lead or bismuth in a cyclotron.Ģ10Po is an alpha emitter that has a half-life of 138.376 days it decays directly to its daughter isotope 206Pb. 210Po (half-life 138.376 days) is the most widely available. They have atomic masses that range from 194u to 218u. Polonium has 25 known isotopes, all of which are radioactive. Other more neutron rich isotopes can be formed by the irradiation of platinum with carbon nuclei. It has been found that the longer-lived isotopes of polonium can be formed by proton bombardment of bismuth using a cyclotron. Only about 100 grams are produced each year, practically all of it in Russia, making polonium exceedingly rare. Polonium may now be made in milligram amounts in this procedure which uses high neutron fluxes found in nuclear reactors. In 1934 an experiment showed that when natural 209Bi is bombarded with neutrons, 210Bi is created, which then decays to 210Po via β decay. Polonium has been found in tobacco smoke from tobacco leaves grown with phosphate fertilizers, though similar amount occur in everything from cherries to human tissue. The amounts in the Earth's crust are not harmful. It is found in uranium ores at about 100 micrograms per metric ton (1 part in 10 10), which is approximately 0.2% of the abundance of radium. Polonium is a very rare element in nature because of the short half-life of all its isotopes. The Curies first separated out polonium from the pitchblende, and then within a few years, also isolated radium. This spurred the Curies on to find additional radioactive elements. The pitchblende, after removal of the radioactive elements uranium and thorium, was more radioactive than both the uranium and thorium put together. This element was the first one discovered by the Curies while they were investigating the cause of pitchblende radioactivity. Polonium may be the first element named to highlight a political controversy. It was Curie's hope that naming the element after her native land would publicize its lack of independence. Poland at the time was under Russian, Prussian, and Austrian partition, and did not exist as an independent country.
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