The ammonium (more obscurely: aminium) cation is a positively charged polyatomic cation with the chemical formula NH4. 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 (NR4), where one or more hydrogen atoms are replaced by organic radical groups (indicated by R).
In the substitutive nomenclature NH4 is denoted by the name azan...
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The ammonium (more obscurely: aminium) cation is a positively charged polyatomic cation with the chemical formula NH4. 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 (NR4), where one or more hydrogen atoms are replaced by organic radical groups (indicated by R).
In the substitutive nomenclature NH4 is denoted by the name azanium instead of ammonium.
The ammonium ion is generated when ammonia, a weak base, reacts with Brønsted acids (proton donors):
The acid dissociation constant (pKa) of NH4 is 9.25.
The ammonium ion is mildly acidic, reacting with Brønsted bases to return to the uncharged ammonia molecule:
Thus, treatment of concentrated solutions of ammonium salts with strong base gives ammonia. When ammonia is dissolved in water, a tiny amount of it converts to ammonium ions:
The degree to which ammonia forms the ammonium ion depends on the pH of the solution....
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