라듐

Radium (Ra) is a radioactive element, found naturally occurring in the environment. Ra is a silvery- white-metallic solid @ 25℃; it tarnishes black when exposed to air. It is an alkaline earth metal; there are 33 isotopes, all of them are unstable. Radium is commonly available as radium bromide (RaBr2 ) or radium chloride (RaCl2 ).

출처Radium is the 85th most abundant element found in the Earth’s crust. Radium is found inthe uranium ores pitchblende and chalcolite, which are both very radioactive. Radium metalexists to the extent of only one part to every three million parts of the uranium ore (pitchblende). Only about one gram of radium is found in every seven or eight tons of uraniumore. This scarcity seems to be the reason that only about five pounds of uranium are producedeach year in the entire world. Uranium ores are found in the states of Utah, New Mexico, andColorado in the United States and in Canada, the Czech Republic, Slovakia, Russia, Zaire,and France.

용도Radium’s most important use is as a source of radiation in industry, medicine, and laboratories. The isotope radium-226, which is the most abundant of all the 25 isotopes and has ahalf-life of 1630 years, is the only useful form of the element. It is used in the medical treatment of malignant cancer growth. It kills cancer cells that have spread throughout the body.Other uses are to produce phosphorescence and fluorescence in organic compounds andfor scintillation screens on instruments used to detect radiation. Radium salts were used in thepast to paint the dials of luminous clock faces that glow in the dark.

정의A white radioactive luminescent metallic element of the alkaline- earth group. It has several short-lived radioisotopes and one long-lived isotope, radium-226 (half-life 1602 years). Radium is found in uranium ores, such as the oxides pitchblende and carnotite. It was formerly used in luminous paints and radiotherapy. Symbol: Ra; m.p. 700°C; b.p. 1140°C; r.d. 5 (approx. 20°C); p.n. 88; r.a.m. 226.0254 (226Ra).