Ammonium group
= Ammonium group
An <ammonium group> is a positively charged tetracoordinate nitrogen unit. It can arise by protonating an amine, while a quaternary ammonium group has four carbon-containing substituents and no nitrogen-bound proton to remove.
These forms therefore differ in acid-base behavior despite sharing a positive nitrogen center. Their charge influences solvation, ion pairing, and interactions with other charged groups.