Quaternary Ammonium Salt Definition:

An ionic compound containing a positively charged nitrogen atom connected to four alkyl groups.

Quaternary Ammonium Salt Explained:

Salts that are derived from ammonium where nitrogen atoms are bonded to 4 organic groups. The word “salt” in quaternary ammonium salt is a misnomer because a quaternary ammonium salt cannot be prepared by an acid-base reaction.