Tertiary is a term used in organic chemistry to classify various types of compounds (e. g. alcohols, alkyl halides, amines) or reactive intermediates (e. g. alkyl radicals, carbocations).

	Red highlighted central atoms in various groups of chemical compounds. Tertiary central atoms compared with primary, secondary and quaternary central atoms.
	primary	secondary	tertiary	quaternary
Carbon atom in an alkane
Alcohol				does not exist
Amine
Amide				does not exist
Phosphine

• Primary (chemistry)
• Secondary (chemistry)
• Quaternary (chemistry)