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92. UraniumName: Uranium
Uranium is of great interest because of its application to nuclear power and nuclear weapons. Uranium contamination is an emotive environmental problem. It is not particularly rare and is more common than beryllium or tungsten for instance. Uranium gives interesting yellow and green colours and fluorescence effects when included to glass in conjunction with other additives. When refined, uranium is a silvery white, weakly radioactive metal, which is slightly softer than steel. It is malleable, ductile, and slightly paramagnetic. Uranium metal has very high density, 65% more dense than lead. When finely divided, it can react with cold water; in air, uranium metal becomes coated with uranium oxide. Uranium in ores can be extracted and chemically converted into uranium dioxide or other chemical forms usable in industry. The use of uranium, in its natural oxide form, dates back to at least 79 AD, when it was used to add a yellow color to ceramic glazes (yellow glass with 1% uranium oxide was found near Naples, Italy). The discovery of the element is credited to the German chemist Martin Heinrich Klaproth who in 1789 found uranium as part of the mineral called pitchblende. It was named after the planet Uranus, which had been discovered eight years earlier. It was first isolated as a metal in 1841 by Eugene-Melchior Peligot. Uranium was found to be radioactive by French physicist Henri Becquerel in 1896, who first discovered the process of radioactivity with uranium minerals. All isotopes and compounds of uranium are toxic and radioactive. Toxicity can be lethal. In less than lethal doses toxicity is limited primarily to recoverable kidney damage. Radiological effects are systemic. Uranium compounds in general are poorly absorbed by the lining in the lungs and may remain a radiological hazard indefinitely. Finely-divided uranium metal presents a fire hazard. Quick links
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