Isotopes of plutonium

Isotopes of plutonium (₉₄Pu)

Main isotopes Decay Isotope abun­dance half-life (t1/2) mode pro­duct 236Pu synth 2.858 y α 232U SF – 238Pu trace 87.7 y α 234U SF – 239Pu trace 2.411×104 y α 235U SF – 240Pu trace 6.561×103 y α 236U SF – 241Pu synth 14.33 y β− 241Am α 237U SF – 242Pu synth 3.75×105 y α 238U SF – 244Pu trace 8.13×107 y α 240U SF –

Plutonium (₉₄Pu) is an artificial element, except for trace quantities resulting from neutron capture by uranium, and thus a standard atomic weight cannot be given. Like all artificial elements, it has no stable isotopes. It was synthesized before being found in nature, with the first isotope synthesized being ²³⁸Pu in 1940. Twenty-two plutonium radioisotopes have been characterized. The most stable are ²⁴⁴Pu with a half-life of 81.3 million years, ²⁴²Pu with a half-life of 375,000 years, ²³⁹Pu with a half-life of 24,110 years, and ²⁴⁰Pu with a half-life of 6,561 years. This element also has eight meta states; all have half-lives of less than one second.

The known isotopes of plutonium range from ²²⁶Pu to ²⁴⁷Pu. The primary decay modes before the most stable isotope, ²⁴⁴Pu, are spontaneous fission and alpha decay; the primary mode after is beta emission. The primary decay products before ²⁴⁴Pu are isotopes of uranium and neptunium (not considering fission products), and the primary decay products after are isotopes of americium.