A synthetically produced transuranium element. It does not exist in measurable amounts in the earth's crust. Glenn Seaborg and his colleagues at the University of California at Berkeley first prepared this element in 1940. Plutonium is by far the most important of all transuranium elements because one of its isotopes, plutonium-239, can be fissioned. Plutonium-239 is the only isotope other than uranium-235 that is readily available for use in nuclear weapons and nuclear reactors. Unfortunately plutonium is also one of the most toxic substances known to humans, making its commercial use a serious environmental hazard. With a half-life of 24,000 years, the isotope presents difficult disposal problems.

See Also

Nuclear Fission; Nuclear Power