Radium

270 px|thumb| Radium is a chemical element; it has 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 reacts with nitrogen (rather than oxygen) upon exposure to air, forming a black surface layer of radium nitride (Ra3N2). All isotopes of radium are radioactive, the most stable isotope being radium-226 with a half-life of 1,600 years. When radium decays, it emits ionizing radiation as a by-product, which can excite fluorescent chemicals and cause radioluminesce

non-SI unit of radioactivity

women who died from radium while working as watch painters

Radium nuclides with different mass numbers

thumb|A bottle of Radithor at the National Museum of Nuclear Science & History in New Mexico, United States Radithor was a radioactive patent medicine brand of distilled water containing at least each of the radium-226 and 228 isotopes, sold in bottles. In 1932, the illness and death of business magnate Eben Byers was unambiguously linked to his fervent use of Radithor, leading to the collapse of the radium fad and the strengthening of regulatory control of pharmaceutical and radioactive products in the United States.

US company

Geological phenomenon