Definition of alkyl groups

Univalent groups derived from alkanes by removal of a hydrogen atom from any carbon atom: CnH2n+1-. The groups derived by removal of a hydrogen atom from a terminal carbon atom of unbranched alkanes form a subclass of normal alkyl (n-alkyl) groups: H[CH2]n-. NOC Rule A-1.2. The groups RCH2-, R2CH- (R not equal to H), and R3C- (R not equal to H) are primary, secondary and tertiary alkyl groups respectively. See also cycloalkyl groups. Cf. hydrocarbyl groups.