ammonium
noun
am·mo·ni·um
ə-ˈmō-nē-əm 
: an ion NH4+ derived from ammonia by combination with a hydrogen ion and known in compounds (such as salts) that resemble in properties the compounds of the alkali metals
Examples of ammonium in a Sentence
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Most disinfectant wipes contain ammonium compounds and some kind of alcohol for killing bacteria and viruses.
—
Brandee Gruener, Southern Living, 11 Nov. 2025
But even more exciting is the discovery of nitrogen fixation, a process in which certain microbes called diazotrophs convert atmospheric nitrogen gas into ammonium, a form phytoplankton can use.
—Pranjal Malewar, New Atlas, 7 Nov. 2025
The change resulted in the formation of hydrogen bonds connecting the ammonium group to the lead iodide fragments, thereby getting the 2D layer to stick to the pure inorganic perovskite.
—Mrigakshi Dixit, Interesting Engineering, 8 Oct. 2025
Each of the five experiments produced carbon monoxide, cyanate, and ammonium — compounds that were detected in Enceladus' plumes by NASA's Cassini spacecraft in 2005.
—Sharmila Kuthunur, Space.com, 12 Sep. 2025
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Brandee Gruener, Southern Living, 11 Nov. 2025
But even more exciting is the discovery of nitrogen fixation, a process in which certain microbes called diazotrophs convert atmospheric nitrogen gas into ammonium, a form phytoplankton can use.
—Pranjal Malewar, New Atlas, 7 Nov. 2025
The change resulted in the formation of hydrogen bonds connecting the ammonium group to the lead iodide fragments, thereby getting the 2D layer to stick to the pure inorganic perovskite.
—Mrigakshi Dixit, Interesting Engineering, 8 Oct. 2025
Each of the five experiments produced carbon monoxide, cyanate, and ammonium — compounds that were detected in Enceladus' plumes by NASA's Cassini spacecraft in 2005.
—Sharmila Kuthunur, Space.com, 12 Sep. 2025
See All Example Sentences for ammonium
Cite this Entry
“Ammonium.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/ammonium. Accessed 18 Nov. 2025.
Copy CitationKids Definition
ammonium
noun
am·mo·ni·um
ə-ˈmō-nē-əm
: an ion that comes from the combination of ammonia with a hydrogen ion
Medical Definition
ammonium
noun
am·mo·ni·um
ə-ˈmō-nē-əm
: an ion NH4+ derived from ammonia by combination with a hydrogen ion and known in organic compounds (as quaternary ammonium compounds) and in compounds (as salts) that resemble in properties the compounds of the alkali metals
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