Illustrated Glossary of Organic Chemistry

Quaternary ammonium salt (4^o ammonium salt): An ammonium salt in which the nitrogen atom bearing the +1 formal charge has four carbon-nitrogen single bonds (i.e., it is bonded to four carbon groups).


Methyl ammonium chloride A primary (1^o) ammonium salt		Dimethyl ammonium chloride A secondary (2^o) ammonium salt		Trimethyl ammonium chloride A tertiary (3^o) ammonium salt		Tetramethyl ammonium chloride A quaternary (4^o ) ammonium salt		1,1-diphenyl pyrrolidinium bromide A quaternary (4^o) ammonium salt