A naturally radioactive, silvery, metallic transuranic element, occurring in uranium ores and produced unnaturally by neutron bombardment of uranium. Its longest-lived isotope is Pu 244 with a half-life of 76 million years. It is a radiological poison, specifically soaked up by bone tissue marrow, and is used, especially the highly fissionable isotope Pu 239, as a reactor fuel plus atomic tools. Atomic quantity 94; melting point 640°C; boiling-point 3,235°C; specific gravity 19.84; valence 3, 4, 5, 6. See dining table at factor.
The transuranic substance element with atomic number 94 and logo Pu.
a great silvery grey radioactive transuranic factor whose atoms can be split whenever bombarded with neutrons; present in small volumes in uranium ores it is typically synthesized in atomic reactors; 13 isotopes are known with the most crucial being plutonium 239