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Also, it is cylindrically symmetric around the bonding axis, so this is how we know that it's a sigma orbital.
此外，它关于键轴是圆柱对称的，这就是为什么我们知道它是sigma轨道。
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So z equals 7 -- this is the cut-off where, in fact, the sigma orbital is going to be higher in energy than the pi 2 p orbitals.
所以z等于7-这是分界点，实际上，sigma轨道能量,要比π2p轨道高。
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There is a sigma orbital.
有一个sigma轨道。
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Another thing I want to point out about every sigma orbital that you see, and it will make more sense when we contrast it with pi orbitals later.
另外一个我要指出的事情就是,关于每个sigma轨道你能看到,当我们把它和π轨道对比的时候会看的更清楚。
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Specifically, it's always the z that forms the sigma orbital, and the reason is at least at a minimum for this class we always define the internuclear axis as the z axis, so this is always the z axis, so it's always going to be the 2 p z's that are coming together head-on.
特别的，z总是形成sigma轨道，这是因为至少在这个课里面,我们总是定义核间轴为z轴，所以这总是z轴，所以2pz轨道总是,朝一个方向出现。
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So we can also name this orbital, and this orbital we're going to call sigma 1 s star.
我们也可以，给这个轨道命名。
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And then this means we'll have a total of sigma1s two electrons in our hydrogen molecule, so we can fill both of those into the sigma 1 s orbital, the bonding orbital. We don't have to put anything into the anti-bonding orbital, so that's great.
我们可以把这两个,都填入，轨道里去，成键轨道,我们不需要把什么放到反键轨道里去，这很好。
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And again, I want you to have practiced drawing these out in the form you always need to start with the sigma and then write the number of the orbital.
同样的，我希望你们,练习画这种图,你总是要从sigma开始,然后写出轨道数目。
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First of all, this is the two s orbitals in hydrogen, 1s plus 1s smearing to give us this sigma molecular orbital.
首先，这是氢气中的两个s轨道，1s与1s轨道重叠,产生sigma分子轨道。
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So this is the 1 s star, sigma 1 s star orbital, and what you have in the center here is a node, right in the center between the two nuclei.
这是1s星，sigma1s星轨道，中间这个是节点，它在两个原子核中间。
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This is sigma star with the antibonding orbital that came from 1s, and it is a molecular orbital.
这是sigma星，来自于1s的反键轨道,它是一个分子轨道。
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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。
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Now we're going to start in with that pi 2 p orbitals, which gives us 1 each, and then two each in those, we'll go up to our sigma 2 p z orbital.
现在我们要填π2p轨道，每个1个，然后每个2个，我们我们填sigma2pz轨道。
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This is, in fact, a sigma 2 p z orbital is what this orbital is called.
这是这个轨道是因为,一个sigma2pz轨道。
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All right, so if we think about b h bond here, again, it's the sigma bond, and we're going to say it's a boron 2 s p 2 hybrid orbital interacting with a hydrogen 1 s orbital.
这可以告诉我们，为什么它倾向于周围只有6个电子，好了，考虑一下这里的BH键,同样的，它是sigma键,我们说。
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The reason that it's a sigma bond is sp3 because the s p 3 hybrid orbital is directly interacting with the 1 s orbital of the hydrogen atom, and that's going to happen on the internuclear axis, they're just coming together.
它是sigma键的原因,是因为,杂化轨道直接和氢原子1s轨道相互作用，它们作用发生在核间轴上，它们会到一起。
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So this is still a sigma it's a sigma 2 p z star orbital.
这还是一个sigma轨道,它是sigma2pz星轨道。
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And we call that, for this case, our sigma 2 s orbital.
对于这种情况，我们可以叫它sigma2s轨道。
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Do you predict that this will be a sigma or a pi orbital?
你们认为这是sigma轨道还是π轨道？
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z And what you need to remember is if the z 8 is equal to eight or greater, such as oxygen being the cut-off point, this sigma 2 p orbital is actually lower in energy than the pi 2 p orbitals, the molecular orbitals.
你们要记住如果,等于或者大于，就像O是分界点，这时sigma2p轨道,比π2p轨道能量更低。
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