플루토늄 (Pu)

발견 과정

발견: 1941 · Glenn Theodore Seaborg

Enrico Fermi and a team of scientists at the University of Rome reported that they had discovered element 94 in 1934. Fermi called the element hesperium and mentioned it in his Nobel Lecture in 1938. The sample actually contained products of nuclear fission, primarily barium and krypton. Nuclear fission, discovered in Germany in 1938 by Otto Hahn and Fritz Strassmann, was unknown at the time.

용도와 활용

At room temperature, pure plutonium is silvery in color but gains a tarnish when oxidized. The element displays four common ionic oxidation states in aqueous solution and one rare one:

동위원소

Twenty-two radioisotopes of plutonium have been characterized, from 226Pu to 247Pu. The longest-lived are 244Pu, with a half-life of 80.8 million years; 242Pu, with a half-life of 373,300 years; and 239Pu, with a half-life of 24,110 years. All other isotopes have half-lives of less than 7,000 years. This element also has eight metastable states, though all have half-lives less than a second. 244Pu has been found in interstellar space and it has the longest half-life of any non-primordial radioisotope. The main decay modes of isotopes with mass numbers lower than the most stable isotope, 244Pu, are spontaneous fission and alpha emission, mostly forming uranium (92 protons) and neptunium (93 protons) isotopes as decay products (neglecting the wide range of daughter nuclei created by fission processes). The main decay mode for isotopes heavier than 244Pu, along with 241Pu and 243Pu, is beta