plutonium 239

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.