On this day in 1898, having recently discovered polonium, future Nobel Prize winners Marie and Pierre Curie discovered the radioactive chemical element radium, a silvery white metal that would be used to treat cancer.
Radium was discovered (1898) by Pierre Curie, Marie Curie, and an assistant, G. Bémont, after Mme Curie had observed that the radioactivity of pitchblende was four or five times greater than that of the uranium it contained and not fully explained on the basis of radioactive polonium, which she had just discovered in pitchblende residues. The new, powerfully radioactive substance followed the behavior of barium, but because its chloride was slightly more insoluble it could be concentrated by fractional crystallization. By 1902, one-tenth gram of pure radium chloride was prepared by refining several tons of pitchblende residues, and by 1910 Mme Curie and André-Louis Debierne had isolated the metal itself.
Radium’s uses all result from its radiations. The most important use of radium was formerly in medicine, principally for the treatment of cancer by subjecting tumors to the gamma radiation of its daughter isotopes. In many therapeutic applications radium has been superseded by the less costly and more powerful artificial radioisotopes cobalt-60 and cesium-137.
An intimate mixture of radium and beryllium is a moderately intense source of neutrons, used for scientific research and for well logging in geophysical prospecting for petroleum.
For these uses, however, substitutes have become available.