pi bond

So we can kind of flip it this way this will be one pi bond, this will be another interacting between these p orbitals.

我们可以把它这样翻一下，这是一个π键，这是另外一个p轨道之间，相互作用的π键。

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Is that a sigma or a pi bond?

这是sigma键还是π键？

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So if we have a single bond here, would you consider that a sigma bond or a pi bond?

如果这里有个单键，你觉得这是sigma键还是π键？

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The reason for bringing on two sets of pi-bond energy data

产生两套π键能数据的原因

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So would you expect this to be a pi bond or a sigma bond her PROFESSOR: OK, so I'm hearing some mixed answers.

你们觉得这是一个π键还是sigma键？，我听到有不同的答案。

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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。

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So it's very important to be keeping in mind that any time you see a double bond, you have a pi bond there, so you're not going to see any rotation around the bond axis.

所以你们要记住，任何时候你们看到一个双键，这里面有π键，你们不会看到关于键轴的任何转动。

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So if I try to rotate my2 atoms, you see that I have to break that pi bond, because they need to be lined up so that the electron density can overlap.

如果我要试着转动两个原子，你会看到我必须要打破一个π键，因为他们需要连接起来，让那些电子能够重叠。

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So our second bond is going to be a pi bond.

第二个键是π键。

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Nano-particles of SiO2 form the hydrogen bond with carbonyl of PI, which changes the geometrical and electronic structure of PI, but the bond order changes a little.

SiO2纳米颗粒与PI上的羰基形成氢键，使得PI的几何结构和电子结构发生了变化，但键级基本没有变化。

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We're already using it up in this pi bond here, so that means we're limited to only two other spots on the molecule, so we have three.

我们已经把它用到这个π键里去了，所以这意味着，我们在分子里只剩下两个位置，所以一共是三个。

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And so both of these lobes together constitute a pi bond.

上下两片叶一起组成了一根π键。

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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？

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So in order to rotate a double bond, you have to actually break the pi bond, so essentially what you're doing is breaking the double bond.

为了能够旋转双键，你必须打破一个π键，本质上我们要做的就是打破双键。

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But once you have a double bond here, we have our pi bond, as well as our sigma bond.

但一旦你有了双键，我们有π键，也有sigma键。

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Now let's think about this first pi bond, which will be above and below the bonding axis.

让我们先来看这个π键，它在键轴的上面和下面。

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