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

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

The airbags use ammonium nitrate gas for instant inflation.

From BBC • Jun. 25, 2025

Davis said six packages of ammonium nitrate were shipped from Park in Seattle to Bartkus.

From Los Angeles Times • Jun. 24, 2025

Ed McMillan had staged the Rad Lab’s most determined search for the isotope by propping a bottle of granular ammonium nitrate in the path of the thirty-seven-inch machine’s neutron beam for several months.

From "Big Science" by Michael Hiltzik