Polonium Polonium was discovered in 1898, in samples of uranium -bearing pitchblende . But the sample was far more radioactive than the uranium should make it. It was suspected that at least one additional radioactive substance was in the mixture. Polonium-210 is the only isotope produced commercially. It is shown here as a thin film on a stainless steel disc, the form in which it is sold as an alpha-particle source for scientific use.
Polonium is used as a neutron source in nuclear reactors and as an alpha-particle generator.
Like other radioactive elements, polonium is a hazardous toxic agent and should be handled with proper protective equipment.