醛(aldehyde):有机化合物的一类,是醛基(-CHO)和烃基(或氢原子)连接而成的化合物。醛基由一個碳原子、一個氫原子及一個雙鍵氧原子組成, is called the aldehyde group. The aldehyde group is also called the formyl or methanoyl group.
Owing to resonance stabilization of the conjugate base, an α-hydrogen in an aldehyde is more acidic than a hydrogen atom in an alkane, with a typical pKa of 17.