a radioactive, metallic chemical element, one of the alkaline-earth metals, found in very small amounts in pitchblende and other minerals containing uranium: it undergoes spontaneous atomic disintegration through several stages, emitting alpha, beta, and gamma rays and finally forming an isotope of lead: radium is used in neutron sources and in the treatment of cancer and other diseases: symbol, Ra; at. no. 88
Origin of radiumModern Latin from Classical Latin radius, ray (see radius) + -ium: so named (1898), because it emits rays, by Pierre and Marie Curie and G. Bémont (1857-1932), French chemist
A rare, brilliant white, luminescent, highly radioactive metallic element found in very small amounts in uranium ores, having more than 40 isotopes and isomers with mass numbers between 201 and 234, of which Ra-226 with a half-life of 1,600 years is the most common. It is used as a neutron source for some research purposes and was formerly widely used in cancer radiotherapy and as a constituent of luminescent paints. Atomic number 88; melting point 696°C; boiling point 1,737°C; specific gravity 5; valence 2. See Periodic Table.
Origin of radiumLatin radius ray ; see ray 1. -ium
- a radioactive metallic chemical element (symbol Ra) with an atomic number of 88.