Radium is a chemical element with the symbol Ra and atomic number 88. It is the sixth element in group 2 of the periodic table, also known as the alkaline earth metals. Pure radium is silvery-white, but it readily oxidizes on exposure to air, becoming black in color. All isotopes of radium are highly radioactive, with the most stable isotope being radium-226. When isolated, pure radium metal emits a faint glow due to its intense radioactivity.
Radium was discovered in 1898 by Marie Curie and Pierre Curie in pitchblende ore from Bohemia (now part of the Czech Republic). They separated out radium chloride by repeated crystallization; however, they were not able to isolate pure radium metal until 1902. Radium was immediately hailed as a wonder element for its radioactivity, which was then thought to be beneficial for health. It was used in various so-called “radiation therapy” treatments and sold as tonics and elixirs. However, it was soon realized that even small amounts of ingested radium can cause severe health problems, including cancer. As a result, its use has been largely discontinued except for certain medical applications where its radioactivity can be harnessed for treatment purposes.
Radium is an intensely radioactive metal that has been used medically and industrially since its discovery over 100 years ago. Although no longer widely used due to safety concerns associated with its radioactivity, it continues to have some important uses in medicine and industry.