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

The reason that I wanted to point out this nodal plane here is because this is why it is called a pi orbital.

我指出这个节面的原因是因为,它就是为什么这个叫做π轨道的原因。

麻省理工公开课 - 化学原理课程节选

Pi orbitals are a molecular orbital that have a nodal plane through the bond axis.

轨道是沿着键轴,有节面的分子轨道。

麻省理工公开课 - 化学原理课程节选

So, if we say that in this entire plane we have zero probability of finding a p electron anywhere in the plane, the plane goes directly through the nucleus in every case but a p orbital, so what we can also say is that there is zero probability of finding a p electron at the nucleus.

而只要是ｐ轨道,这个平面都直接，穿过原子核，那么我们,可以说在原子核上,找到一个ｐ电子的概率为零。

麻省理工公开课 - 化学原理课程节选