Orbital overlap is the merging of orbitals from different atoms into the same region of space, which allows a pair of electrons to be shared and a covalent bond to form. The greater the overlap, the stronger the resulting bond. End-on overlap gives a sigma bond, whereas side-on overlap gives a pi bond.

轨道重叠是不同原子的轨道合并到同一空间区域,从而使一对电子得以共享、形成共价键。重叠越多,所形成的键越强。头碰头的重叠形成 σ 键,而侧向重叠形成 π 键。