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。

youdao

So PI bonds have electron density both above and below the bond axis, but they actually have a nodal plane at this z, this bond axis here.

键在键轴之上，和之下都有电子密度，但它们在z方向有节面，这是键轴的地方。

youdao

But in sigma orbitals, you have no nodal planes along the bond axis, so if we had a nodal plane here, we'd see an area where the wave function was equal to zero.

但在sigma轨道里，沿着轴向是没有节点平面的，如果我们有个节点，我们就会看到某个地方波函数等于0。

youdao

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

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 pi bonds have electron density both above and below the bond axis, but they actually have a nodal plane at this z, this bond axis here.

键在键轴之上,和之下都有电子密度，但它们在z方向有节面，这是键轴的地方。

麻省理工公开课 - 化学原理课程节选

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