ammonium

American  

[uh-moh-nee-uhm] / əˈmoʊ ni əm /

noun

Chemistry.

1. the univalent ion, NH 4 + , or group, NH 4 , which plays the part of a metal in the salt formed when ammonia reacts with an acid.

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ammonium British  

/ əˈməʊnɪəm, -njəm /

noun

1. (modifier) of, consisting of, or containing the monovalent group NH 4 – or the ion NH 4 ⁺

   ammonium compounds

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ammonium Scientific  

/ ə-mō′nē-əm /

1. A positively charged ion, NH ₄, derived from ammonia and found in a wide variety of organic and inorganic compounds. Compounds of ammonium chemically resemble the alkali metals.

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Etymology

Origin of ammonium

< New Latin; ammonia, -ium; coined by J. J. Berzelius in 1808

Compare meaning

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• ammonia vs. ammonium

Example Sentences

In 2024 China accounted for 70% of Russia’s imports of ammonium perchlorate, an essential ingredient in ballistic-missile fuel.

From The Wall Street Journal • Dec. 18, 2025

They also observed that the gene linked to saxitoxin was less common in areas with elevated ammonium levels.

From Science Daily • Dec. 2, 2025

In that moment, Windey ammonium thioglycolate-ed her path to victory, and in the end, she and three fellow “faithfuls” won the game in this week’s finale.

From Los Angeles Times • Mar. 7, 2025

Distillers threw rotten fruit and molasses waste in the gallon to brew with ammonium chloride to produce something called “snake juice,” which was collected by lepers and taken around the city.

From Salon • Feb. 2, 2025

But scientists in the Department of Agriculture had a better idea: Spread the ammonium nitrate on farmland as fertilizer.

From "The Omnivore's Dilemma" by Michael Pollan