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 hydride and hydrogen selenide, and decomposes into its constituent elements, releasing heat in the process. The amount of heat given off in the decomposition of polonium hydride is over 100 kJ/mol, the largest of all the hydrogen chalcogenides. Polonium hydride is a liquid due to van der Waals forces, and not due to the same reason as why water (hydrogen oxide) is liquid (hydrogen bonding). It is predicted that, like the other hydrogen chalcogenides, polonium may form two types of salts: polonide (containing the Po anion) and one from polonium hydride (containing –PoH, which would be the polonium analogue of thiol,