History of chemistry element among the fractions that resulted. Working with the mineral pitchblende, the pair discovered a new radioactive element in 1898. They named the element polonium, after Marie's native country of Poland. On December 21, 1898, the Curies detected the presence of another radioactive material in the pitchblende. They presented this finding to the French Academy of Sciences on December 26, proposing that the new element be called radium. The Curies then went to work isolating polonium and radium from naturally occurring compounds to prove that they were new elements. In 1902, the Curies announced that they had produced a decigram
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,