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...
This is a preview of subscription content, log in via an institution to check access.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Bibliography
Allard, B., Olofsson, U., Torstenfeldt, B. and Kipatski, H. (1983). Sorption Behavior of Actinides in Well-defined Oxidation States. Göteborg: Chalmers University of Technology, Dept. Nuclear Chemistry, 1983–05–15.
Choppin, G. (1983). Solution chemistry of the actinides. Radiochim. Acta, 32, 43–53.
Choppin, G.R. (1992). The role of natural organics in radionuclide migration in natural aquifer systems. Radiochim. Acta, 58/59, 113–120.
Katz, J.J. and Seaborg, G.T. (1957). The Chemistry of the Actinide Elements. New York; John Wiley & Sons, 331 pp.
Lederer, C.M. and Shirley, V.S. (1978). Table of Radioactive Isotopes. New York: John Wiley & Sons.
Schulz, W.W. (1976). The Chemistry of Americium. Techn. Information Center Oak Ridge: ERDA Crit. Rev. Series, TID-26971.
Cross-references
Rights and permissions
Copyright information
© 1998 Kluwer Academic Publishers
About this entry
Cite this entry
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
Download citation
DOI: https://doi.org/10.1007/1-4020-4496-8_7
Publisher Name: Springer, Dordrecht
Print ISBN: 978-0-412-75500-2
Online ISBN: 978-1-4020-4496-0
eBook Packages: Springer Book Archive