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 a volatile liquid at room temperature prone to dissociation; it is thermally unstable. Water is the only other known hydrogen chalcogenide which is a liquid at room temperature; however, this is due to hydrogen bonding. The two oxides PoO and PoO are the products of oxidation of polonium. Halides of the structure PoX, PoX and PoF are known. They are soluble in the corresponding hydrogen halides, i.e., PoCl in HCl, PoBr in HBr and PoI in HI. Polonium dihalides are formed by direct reaction of the elements or by reduction of PoCl with SO and with PoBr with HS at