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.

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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)

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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

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Etymology

Origin of americium

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

Example Sentences

There are already two different drug injections that can be used to treat people who have been exposed to radioactive plutonium, americium or curium.

From BBC • May 16, 2023

Two of nuclear waste’s most problematic ingredients are metals called americium and curium; each has particularly long-lived forms that decay slowly over thousands of years.

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