Sigma that is one PI orbital. There is one sigma, one PI and there is a second PI, and that is how we are getting the triple bond.

那是一个pi轨道，有一个，一个pi，还有第二个pi轨道，这就是我们如何得到三线态的。

youdao

We want to discuss sigma bonds and pi bonds.

我们要讨论sigma键和π键。

youdao

So, as they're very quietly handing out your class notes, let's think about what this bond is here, this boxed bond, is it a pi bond or a sigma bond?

在他们发讲义的同时，我们来看看这个键，方框里的这个键，它是sigma键还是π键？

youdao

This is because most fraternities and sororities are named after a series of Greek letters, such as Alpha Delta Pi or Sigma Phi.

VOA: special.2009.09.25

So let's fill it out in this way, 2p keeping in mind that we're going to fill sigma out the pi 2 p's before the sigma.

让我们这样填上去，记住我们先填π,轨道再填。

麻省理工公开课 - 化学原理课程节选

So that's exactly what our definition of a pi bond is, so we have one sigma bond, and one pi bond.

这是我们对π键的定义，我们有一个sigma键，和一个π键。

麻省理工公开课 - 化学原理课程节选

"There's a general sense of the fun of being a college student, without any of the things that might be in a more adult-oriented college film, " said Mr. Gerson, 46, who went to Cornell University and was a member of the Sigma Pi fraternity.

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