Aldehyde (Carbonyl group) R-(C=O)-H
Amine -- R-N-R
Alcohol (Hydroxyl group) R-OH
Carboxylic Acid (Carboxyl group) -- RCOOH
Amide (Carboxylic acid derivative) R-C=ON-R'
Ester (Carboxylic acid derivative) -- ROOR'
Thiol -- R-SH
Ketone -- R-(C=O)-R'
Ether -- R-O-R'