Marie Curie won the 1911 Nobel Prize in Chemistry for discovering radium and polonium and investigating their properties.
Curie and Pierre Curie announced the discovery of polonium in 1898, naming it after Marie’s homeland, Poland. They identified radium later that year while studying pitchblende, a uranium ore whose radioactivity was stronger than uranium alone.
Her chemistry prize was separate from her 1903 Nobel Prize in Physics, which she shared with Pierre Curie and Henri Becquerel for work on radioactivity. Curie remains the only person to win Nobel Prizes in two different scientific fields.
A common mix-up is confusing her chemistry Nobel with her first Nobel. The 1911 award specifically recognized the discovery and isolation of radium and polonium, plus the study of radium’s nature and compounds.