neptunium

noun

nep·​tu·​ni·​um nep-ˈtü-nē-əm How to pronounce neptunium (audio)
-ˈtyü-
: a radioactive metallic element that is chemically similar to uranium and is obtained in nuclear reactors especially as a by-product in the production of plutonium see Chemical Elements Table

Examples of neptunium in a Sentence

Recent Examples on the Web These decays also contaminate the pit with helium, americium, uranium and neptunium, among other things. Sarah Scoles, Scientific American, 14 Nov. 2023 Other researchers have found that green rust, a highly reactive variety of rust, immobilizes radioactive neptunium. Patrick Morgan, Discover Magazine, 5 Apr. 2011 The technique requires bombarding uranium with a neutron to convert it to an unstable form of the element, which decays into neptunium and then fissile plutonium. Andrew Moseman, Discover Magazine, 25 Mar. 2010 The amount of neptunium found in the air monitor at the school was a thousand times below the regulatory action level, said Mr. Edwards of the DOE. Kris Maher, WSJ, 28 Apr. 2021 Sometime in 2017, the radioactive element neptunium 237 was also detected near the school. The Cincinnati Enquirer, Cincinnati.com, 26 July 2019

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'neptunium.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

Etymology

New Latin, from International Scientific Vocabulary Neptune

First Known Use

1941, in the meaning defined above

Time Traveler
The first known use of neptunium was in 1941

Dictionary Entries Near neptunium

Cite this Entry

“Neptunium.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/neptunium. Accessed 19 Mar. 2024.

Kids Definition

neptunium

noun
nep·​tu·​ni·​um nep-ˈt(y)ü-nē-əm How to pronounce neptunium (audio)
: a radioactive metallic element similar to uranium and obtained in nuclear reactors in the production of plutonium see element

Medical Definition

neptunium

noun
nep·​tu·​ni·​um nep-ˈt(y)ü-nē-əm How to pronounce neptunium (audio)
: a radioactive metallic element that is chemically similar to uranium and is obtained in nuclear reactors as a by-product in the production of plutonium
symbol Np
see Chemical Elements Table

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