Element 95 was named by analogy with the corresponding lanthanide, europium.
Properties
Americium, atomic number 95, was identified in 1944 at the University of Chicago by G.T. Seaborg, R.A. James, L.O. Morgan and A. Ghiorso in the form of isotope 241Am (t 1/2 = 432.6 years) as a product of the multiple neutron capture by 239Pu followed by beta decay of 241Pu. Thirteen man-made isotopes have been prepared with 232, 234 and 237–247 nucleons and half lives ranging from 55 s (232Am) to 7370 years (243Am). The light isotopes up to 240Am decay by electron capture, the isotopes higher than 244 are short-lived β-emitters. Both long-lived isotopes decay by emission of α-particles: 241Am with energies of 5.48 (85.2%) and 5.44 MeV (12.8%), and 243Am with energies of 5.27 (88.1%) and 5.23 (11%) MeV. Only the isotopes 241Am and 243Am are applied in science and technology.
Am metal is silvery and crystallizes at room temperature in a double hexagonal, closest packed structure, with a melting point...
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Janecky, D.R., Runde, W.H., Neu, M.P. (1998). Americium: Element and geochemistry. In: Geochemistry. Encyclopedia of Earth Science. Springer, Dordrecht. https://doi.org/10.1007/1-4020-4496-8_7
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DOI: https://doi.org/10.1007/1-4020-4496-8_7
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