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americium

American  
[am-uh-rish-ee-uhm] / ˌæm əˈrɪʃ i əm /

noun

Chemistry.
  1. a transuranic element, one of the products of high-energy helium bombardment of uranium and plutonium. Am; 95.


americium British  
/ ˌæməˈrɪsɪəm /

noun

  1. a white metallic transuranic element artificially produced from plutonium. It is used as an alpha-particle source. Symbol: Am; atomic no: 95; half-life of most stable isotope, 243 Am: 7.4 × 10³ years; valency: 2,3,4,5, or 6; relative density: 13.67; melting pt: 1176°C; boiling pt: 2607°C (est)

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

americium Scientific  
/ ăm′ə-rĭsh′ē-əm /
  1. Symbol Am A synthetic, silvery-white, radioactive metallic element of the actinide series that is produced artificially by bombarding plutonium with neutrons. Americium is used as a source of alpha particles for smoke detectors and gamma rays for industrial gauges. Its most stable isotope has a half-life of 7,950 years. Atomic number 95; specific gravity 11.7; valence 3, 4, 5, 6.

  2. See Periodic Table


Etymology

Origin of americium

An Americanism dating back to 1945–50; Americ(a) + -ium


Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

Alternatively, Cotruvo suggests, captured americium and curium could be recycled back into nuclear fuel.

From Scientific American ● Dec. 28, 2021

Spent fuel rods contain a variety of products, consisting of unstable nuclei ranging in atomic number from 25 to 60, some transuranium elements, including plutonium and americium, and unreacted uranium isotopes.

From Textbooks ● Feb. 14, 2019

Inhalation of the particles, which included uranium, thorium, plutonium and americium, can increase the risk of cancer.

From Seattle Times ● Jun. 14, 2018

Power would come from a tiny radioactive source like americium, the element in smoke detectors.

From New York Times ● Apr. 12, 2016

More tests confirmed that two radioactive particles, isotopes of americium and plutonium, were found on aboveground air filters.

From BBC ● Mar. 6, 2014

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