So even though we see a nodal plane down the center, I just want to really point out that it's only when we have a nodal plane in the internuclear or the bond axis that we're calling that a pi orbital.

虽然在中间有个节面，我想要指出的是,只有节面在核间轴,或者键轴上时,我们才叫它π轨道。

麻省理工公开课 - 化学原理课程节选

If we're talking about a single bond, we're talking about 2 orbitals overlapping in the internuclear axis.

如果我们讨论的是单键，我们讨论的是两个轨道,在核间轴中重叠。

麻省理工公开课 - 化学原理课程节选

And remember for this class, we always define z as the internuclear or the bond axis.

记住在我们的课堂上，我们总是把z方向定义为核间轴的方向。

麻省理工公开课 - 化学原理课程节选

A triple bond, again is going to have one sigma bond on the internuclear axis.

一个三键，同样的也有沿着核间轴sigma键。

麻省理工公开课 - 化学原理课程节选

All right, so what we see here is we have our sigma bond that's along the internuclear axis here, but we also have a pi bond, because each of these atoms now has electrons in it's in a p orbital, so we're going to overlap of electron density above and below the bond.

这里我们看到sigma键,是沿着核间轴的，但我们还有一个π键，因为每个原子的p轨道上,都有电子，所以电子密度在键的上面,和下面都有电子密度交叠。

麻省理工公开课 - 化学原理课程节选