一般认为,碳原子是SP~2杂化,其碳氧双键由一个σ键和一个π键组成,碳原子具有三角形的平面结构。由于氧的诱导效应,碳氧双键是极化的,因此羰基是一个极性基因,其负极朝向氧的一端,正极朝向碳的一端,带部分正电荷的碳具有较大的化学活泼性,因此,一般易和一系列亲核试剂发生亲核加成,且加成的方向总是试剂的亲核部分加在 It is generally believed that the carbon atom is a sp ~ 2 hybrid with a carbon-oxygen double bond consisting of a σ bond and a π bond, and the carbon atom has a triangular planar structure. Because of the oxygen inducing effect, the carbon-oxygen double bond is polarized, so carbonyl is a polar gene whose negative electrode is toward one end of the oxygen and the positive electrode is toward the carbon end. The partially positively charged carbon has greater chemical activity, Therefore, it is generally easy to nucleophilic addition with a series of nucleophiles, and the addition is always in the nucleophilic part of the reagent