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; see 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

That disaster “brought about new regulations for the chemical manufacturing industry,” the museum said, including requiring cool temperatures and special containers for shipping ammonium nitrate and banning storage near other reactive materials.

From Los Angeles Times • May 23, 2026

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

Growing even modest quantities of mycoprotein requires significant inputs, and the spores must be cultivated in large metal tanks filled with sugar-rich feedstock and added nutrients such as ammonium sulfate.

From Science Daily • Nov. 21, 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 that’s inside our house. The outside one’s for bodily waste, full of quaternary ammonium compound chemicals. You know, like that stinky blue soup at the bottom of a porta potty.”

From "Dry" by Neal Shusterman and Jarrod Shusterman