Ammonium
![2-D skeletal version of the ammonium ion](/Images/godic/202412/22/Ammonium-2D.svg4437.png")
![Fumes from hydrochloric acid and ammonia forming a white cloud of ammonium chloride.](/Images/godic/202412/22/Hydrochloric_acid_ammonia4438.jpg")
![](/Images/godic/202412/22/Dimethylammonium-formation-2D4438.png")
The ammonium cation is a positively charged polyatomic ion with the chemical formula NH+
4. It is formed by the protonation of ammonia (NH3). Ammonium is also a general name for positively charged or protonated substituted amines and quaternary ammonium cations (NR+
4), where one or more hydrogen atoms are replaced by organic groups (indicated by R).