Polonium years) can be made through the alpha, proton, or deuteron bombardment of lead or bismuth in a cyclotron. Tentatively called "radium F", polonium was discovered by Marie and Pierre Curie in 1898, and was named after Marie Curie's native land of Poland (). Poland at the time was under Russian, German, and Austro-Hungarian partition, and did not exist as an independent country. It was Curie's hope that naming the element after her native land would publicize its lack of independence. Polonium may be the first element named to highlight a political controversy. This element was the first one discovered by
Polonium dioxide the scarcity of polonium in nature and the high temperatures (250 °C) required to form the dioxide. Polonium dioxide is prepared by reacting elemental polonium with oxygen at 250 °C or by thermal decomposition of polonium(IV) hydroxide (PoO(OH)), polonium disulfate (Po(SO)), polonium selenate (Po(SeO)), or polonium tetranitrate (Po(NO)). When placed in hydrogen, polonium dioxide is slowly reduced to metallic polonium at 200 °C; the same reduction occurs at 250 °C in ammonia or hydrogen sulfide. When heated in sulfur dioxide at 250 °C, a white compound is formed, possibly a polonium sulfite. When polonium dioxide is hydrated, polonous acid (HPoO),