plutonium

plu·to·ni·um   (plōō-tō'nē-əm)    n.   Symbol Pu A naturally radioactive, silvery, metallic transuranic element, occurring in uranium ores and produced artificially by neutron bombardment of uranium. Its longest-lived isotope is Pu 244 with a half-life of 80 million years. It is a radiological poison, specifically absorbed by bone marrow, and is used, especially the highly fissionable isotope Pu 239, as a reactor fuel and in nuclear weapons. Atomic number 94; melting point 640°C; boiling point 3,228°C; specific gravity 19.84; valence 3, 4, 5, 6. See Table at element. [After the dwarf planet Pluto (from the fact that it follows neptunium in the periodic table).]

plutonium [(plooh-toh-nee-uhm)]

A radioactive chemical element that is artificially derived from uranium.

Note: Plutonium is used in nuclear reactors.

plutonium 

Main Entry: plu·to·ni·um
Pronunciation: plü-'tO-nE-&m
Function: noun
: a radioactive metallic element similar chemically touranium that is formed as the isotope 239 by decay of neptunium and found in minute quantities in pitchblende, that undergoes slow disintegration with the emission of an alpha particle to form uranium235, and that is fissionable with slow neutrons to yield atomic energy —symbol Pu; —see ELEMENT table

plutonium plu·to·ni·um (pl&oomacr;-tō'nē-əm)
n.
Symbol Pu
A naturally radioactive, metallic transuranic element, occurring in uranium ores or produced artificially by neutron bombardment of uranium. Its longest-lived isotope is Pu 244 with a half-life of 77 million years. Atomic number 94; melting point 640°C; boiling point 3,228°C; specific gravity 19.84; valence 3, 4, 5, 6.

plutonium   (pl-tō'nē-əm)  Pronunciation Key  Symbol Pu A silvery, radioactive metallic element of the actinide series that has the highest atomic number of all naturally occurring elements. It is found in minute amounts in uranium ores and is produced artificially by bombarding uranium with neutrons. It is absorbed by bone marrow and is highly poisonous. Plutonium is used in nuclear weapons and as a fuel in nuclear reactors. Its longest-lived isotope is Pu 244 with a half-life of 76 million years. Atomic number 94; melting point 640°C; boiling point 3,232°C; specific gravity 19.84; valence 3, 4, 5, 6. See Periodic Table.

plutonium

radioactive chemical element of the actinoid series of the periodic table, atomic number 94. It is the most important transuranium element because of its use as fuel in certain types of nuclear reactors and as an ingredient in nuclear weapons. Plutonium, warm because of energy released in alpha decay, is a silvery metal that takes on a yellow tarnish in air. The element was first detected (1941) as the isotope plutonium-238 by Glenn T. Seaborg, Joseph W. Kennedy, and Arthur C. Wahl, who produced it by deuteron bombardment of uranium-238 in the 60-inch cyclotron at Berkeley, California. Traces of plutonium have subsequently been found in uranium ores, where it is not primeval but naturally produced by neutron irradiation

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