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uranium
uranium , radioactive metallic chemical element; symbol U; at. no. 92; at. wt. 238.0289; m.p. 1,132°C; b.p. 3,818°C; sp. gr. 19.1 at 25°C; valence +3, +4, +5, or +6.
Properties
Uranium is a hard, dense, malleable, ductile, silver-white, radioactive metal of the actinide series...
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pitchblende
pitchblende , dark, lustrous, heavy mineral, a source of radium and uranium. Largely natural uranium oxides, triuranium octaoxide (U 3 O 8 ) and uranium dioxide (UO 2 ), it usually contains some lead and variable amounts of thorium and rare-earth elements. It is massive in form, frequently with a bo...
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radium
radium [Lat. radius =ray], radioactive metallic chemical element; symbol Ra; at. no. 88; at. wt. 226.0254; m.p. 700°C; b.p. 1,140°C; sp. gr. about 6.0; valence +2. Radium is a lustrous white radioactive metal. It is an alkaline-earth metal ; in its chemical properties it closely resembles...
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actinium series
actinium series natural radioactive decay series beginning with uranium -235 (also called actinouranium) and ending with lead -207. See radioactivity .
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thorium
thorium [from Thor ], radioactive chemical element; symbol Th; at. no. 90; at. wt. 232.0381; m.p. about 1,750°C; b.p. about 4,790°C; sp. gr. 11.7 at 20°C; valence +4.
Thorium is a soft, ductile, lustrous, silver-white, radioactive metal. At ordinary temperatures it has a face-cent...
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Harz
Harz , mountain range, northern Germany, extending c.60 mi (100 km) between the Elbe and Leine rivers. The rugged mountains were once densely forested. They culminate in Brocken peak (3,747 ft/1,142 m high). The region has good waterpower potential, and intensive uranium-ore prospecting began there ...
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Central African Republic
Central African Republic republic (2005 est. pop. 3,800,000), 240,534 sq mi (622,983 sq km), central Africa. The landlocked nation is bordered by Chad (N), Sudan (E), Congo (Kinshasa) and Congo (Brazzaville) (S), and Cameroon (W). Bangui is the capital and largest city.
Land and People
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Port Hope
Port Hope town (1991 pop. 11,505), SE Ont., Canada, on Lake Ontario, E of Toronto. It has a large plant for refining uranium ore and is a summer resort.
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actinium
actinium [Gr.,=like a ray], radioactive chemical element; symbol Ac; at. no. 89; at. wt. 227.0278; m.p. about 1,050°C; b.p. 3,200°C±300°C; sp. gr. 10.07; valence +3. Actinium is a silver-white metal with a cubic crystalline structure. It is found with uranium minerals in pitchbl...
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Kazakhstan
Kazakhstan or Kazakstan , officially Republic of Kazakhstan, republic (2005 est. pop. 15,186,000), c.1,050,000 sq mi (2,719,500 sq km), central Asia. It borders on Siberian Russia in the north, China in the east, Kyrgyzstan, Uzbekistan, and Turkmenistan in the south, and the Caspian Sea and Euro...
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