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

How does ammonium compare to similar and commonly confused words? Explore the most common comparisons:

• ammonia vs. ammonium

Explanation

Ammonium is an ionic compound made of nitrogen and hydrogen, commonly found in household cleaners and fertilizers. Derived from ammonia, ammonium behaves like an alkali metal ion. This means that it can easily bond with other elements, making it versatile and effective in various applications. For example, ammonium is a key ingredient in cleaning products, where it helps break down dirt and grime, making surfaces shine. In fertilizers, ammonium provides essential nutrients that help plants grow strong and healthy.

Example Sentences

To create the effect, the team carefully adjusted the composition of the metal oxide by adding very small amounts of hydrogen and ammonium.

From Science Daily • Dec. 24, 2025

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

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

Because ammonium nitrate, the main ingredient in many explosives, happens to be an excellent source of nitrogen.

From "The Omnivore's Dilemma" by Michael Pollan