Marie Curie Isolates Radium

Marie Curie and assistant Andre Debierne processed several tons of pitchblende ore at a converted shed in Paris to isolate one-tenth of a gram of pure radium chloride. The Curies had announced radium's existence in December 1898 alongside their discovery of polonium, but isolating the element required years of laborious chemical separation. Marie determined radium's atomic weight at 225.93, confirming it as a distinct element. The isolated material's intense radioactivity enabled medical applications in tumor treatment and provided physicists with a concentrated source for studying atomic structure.