Polonium the Curies while they were investigating the cause of pitchblende radioactivity. Pitchblende, after removal of the radioactive elements uranium and thorium, was more radioactive than the uranium and thorium combined. This spurred the Curies to search for additional radioactive elements. They first separated out polonium from pitchblende in July 1898, and five months later, also isolated radium. German scientist Willy Marckwald successfully isolated 3 milligrams of polonium in 1902, though at the time he believed it was a new element, which he dubbed "radio-tellurium", and it was not until 1905 that it was demonstrated to be the same as polonium.
Polonium room temperature. Tetrahalides can be obtained by reacting polonium dioxide with HCl, HBr or HI. Other polonium compounds include potassium polonite as a polonite, polonate, acetate, bromate, carbonate, citrate, chromate, cyanide, formate, (II) and (IV) hydroxides, nitrate, selenate, selenite, monosulfide, sulfate, disulfate and sulfite. Oxides Hydrides Halides Polonium has 33 known isotopes, all of which are radioactive. They have atomic masses that range from 188 to 220 u. Po (half-life 138.376 days) is the most widely available and is made via neutron capture by natural bismuth. The longer-lived Po (half-life years, longest-lived of all polonium isotopes) and Po (half-life 2.9