Primary 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.

Primary central atoms compared with secondary, tertiary and quaternary central atoms.

primary secondary tertiary quaternary
Carbon atom in an alkane
Alcohol does not exist
Amine
Amide does not exist
Phosphine

See also

References