Polonium in the Earth's crust are not harmful. Polonium has been found in tobacco smoke from tobacco leaves grown with phosphate fertilizers. Because it is present in small concentrations, isolation of polonium from natural sources is a tedious process. The largest batch of the element ever extracted, performed in the first half of the 20th century, contained only (9 mg) of polonium-210 and was obtained by processing 37 tonnes of residues from radium production. Polonium is now usually obtained by irradiating bismuth with high-energy neutrons or protons. In 1934, an experiment showed that when natural Bi is bombarded with neutrons, Bi
Polonium dioxide Polonium dioxide Polonium dioxide (also known as polonium(IV) oxide) is a chemical compound with the formula PoO. It is one of three oxides of polonium, the other two being polonium monoxide (PoO) and polonium trioxide (PoO). It is a pale yellow crystalline solid at room temperature. Under lowered pressure (such as a vacuum), it decomposes into elemental polonium and oxygen at 500 °C. It is the most stable oxide of polonium and is an interchalcogen. At room temperature, polonium dioxide has a face-centered cubic (fluorite) crystal structure; upon heating to high temperatures, it crystallises in the tetragonal crystal system. The