The compound NH3 contains one atom of nitrogen and three atoms of hydrogen, whereas NH4 contains one atom of nitrogen and four atoms of hydrogen. NH3 is the chemical formula for ammonia, and NH4 is the chemical formula for ammonium.
Both ammonia and ammonium are cations, meaning that they each carry a positive charge, which is +1 for both ions. Ammonia is commonly found in cleaning supplies, pharmaceuticals and fertilizers, while ammonium is most often used industrially to create chemicals such as ammonium carbonate, ammonium chloride and ammonium nitrate. In the laboratory, ammonium can be formed through a reaction of ammonia with an ion such as B?, H+ or H3O+. Conversely, ammonium can be used to form ammonia by mixing it with a strong base. NH4 has a molar mass of 18.03 grams per mole, compared to a molar mass of 17.03 grams per mole for NH3. The lower mass of NH3 is due to the absence of one hydrogen atom. Ammonia takes the form of a colorless gas and is considered toxic, requiring special procedures for storage and disposal. Ammonium, which is also toxic, can be found naturally in the waste products of animals and is an important source of nitrogen for some types of plants.