Polonium is a metalloid that is silver colored solid in its natural solid state. Polonium is highly radioactive and extremely unstable. Polonium has an atomic weight of 209, a melting point of 489 °F, and a boiling point of 1764 °F. Polonium does not have many uses due to its radioactivity. Some of the few uses of polonium include: as an alloy for a source of neutrons, as an atomic heat source, and sometimes it is used as a poison.