americium
The Columbia Encyclopedia, Sixth Edition | Date: 2008
americium , artificially produced radioactive chemical element; symbol Am; at. no. 95; mass no. of most stable isotope 243; m.p. about 1,175°C; b.p. about 2,600°C; sp. gr. 13.67 at 20°C; valence +2, +3, +4, +5, or +6. Americium is a silver-white metal thought to have either a loose-packed cubic or a close-packed double hexagonal crystalline structure. The pure metal has been prepared by reduction of americium trifluoride with barium vapor at about 1,100°C. It tarnishes slowly in dry air. All 16 known isotopes are radioactive. Americium-243, the most stable isotope, has a half-life of over 7,300 years. Americium-241, which has a half-life of about 430 years, is more often used in chemical investigations, since it is easily prepared in a fairly pure form; it is also used in industrial measuring devices, radiology, and household smoke detectors. The fourth transuranium element to be synthesized, Americium is a member of the actinide series in Group 3 of the periodic table . It was discovered in 1944 by Glenn T. Seaborg , Ralph A. James, Leon O. Morgan, and Albert Ghiorso, who bombarded plutonium-239 with neutrons to form plutonium-241, which decays to form americium-241.
Author not available, AMERICIUM.,
The Columbia Encyclopedia, Sixth Edition 2008
The Columbia Encyclopedia, Sixth Edition. Copyright 2008 Columbia University Press
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Americium Spread To Pa. Lab Contamination From LANL Not Serious, Officials Say
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; Contamination from radioactive americium from a Los Alamos National Laboratory ... about 60 to 350 times less than that. The americium-241 contamination was first detected ... report from LANL explains how low-level americium-241 radioactivity was inadvertently transmitted ...
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Explosive secrets.(it has been widely known that plutonium and enriched uranium can be used to make nuclear weapons, but it also possible to make such a weapon using neptunium and americium )(Brief Article)
Bulletin of the Atomic Scientists; 3/1/1999; Rothstein, Linda; 787 words
; ... be concerned about the neptunium and americium found in nuclear waste streams, because ... devices using neptunium 237. Neptunium and americium--man-made materials produced when nuclear ... Albright and Barbour say that neptunium and americium have received little attention because ...
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HOW STUFF WORKS: ; Radioactive americium controls smoke detectors
Charleston Gazette; 5/5/2008; Marshall Brain; 591 words
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GREECE: PLUTONIUM AND AMERICIUM FOUND BURRIED IN FOREST.
Europe Environment; 2/6/2001; 234 words
; ... the presence of a total of about 3 grams of plutonium and americium. EEAE President Leonidas Kamarinopoulos indicated that the ... plutonium, which does not occur naturally, is highly carcinogenic. Americium is likewise a radioactive derivative. The EEAE has taken steps ...
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Earth To Mars In TWo Weeks.(design of americium-fueled nuclear rocket)(Brief Article)
Popular Mechanics; 3/1/2001; 143 words
; ... nuclear rockets of the 1960s that used uranium and plutonium fuels, the new engine would be powered by a form of the element americium (Am-242), says its designer, Yigal Ronen of Ben-Gurion University of the Negev in Israel. The advantage of Am-242 is that ...
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