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So we can think about now doing bonding, and now we have four equal orbitals with one electronic each.
我们现在可以考虑成键了，现在我们有4个等价的轨道，每个上面有1个电子。
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And so this lower level is called a bonding orbital, and it is a bonding molecular orbital.
所以能级较低的轨道叫做成键轨道，这就是成键分子轨道。
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And what you find is when you have a bonding orbital, the energy decreases compared to the atomic orbitals.
你们发现当你有个成键轨道的时候，相比原子轨道能量要降低。
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It turns out that the antibonding orbital is a little bit higher from the atomic orbital level than the bonding orbital is lower.
这证明了,反键轨道,比原子轨道高,成键轨道比原子轨道第。
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So, we'll start today talking about the two kinds of molecular orbitals, we can talk about bonding or anti-bonding orbitals.
今天我们先来,讨论两种分子轨道，我们要讨论成键和反键轨道。
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So specifically, what we do associate them instead is within molecular orbitals, and what we say is that they can be either in bonding or anti-bonding orbitals.
特别的，我们把它们和,分子轨道相联系起来，我们说它们可以成为,成键轨道或者反键轨道。
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so you can see that there is going to be two sets in antibonding, three sets in bonding for a net of one, giving us the single bond.
因此你能看到,反键轨道上有两组，三组成键，得到一组净成键，所以成的是单键。
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And the other thing to point out is that the energy that an anti-bonding orbital is raised by, is the same amount as a bonding orbital is lowered by.
另外一个要指出的事情是,反键轨道引起的能量升高，和成键轨道引起的能量降低是相同的。
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When we talk about p orbitals the phase of the orbital becomes important once we talk about bonding, which hopefully you were happy to hear at the beginning of class we will get to soon.
对于ｐ轨道,当我们讨论到成键时，轨道的相位就变得非常重要了,这个我们马上就要讲到了。
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Now, from your book as well, this is the pz's of the two atomic orbitals forming the bonding orbital.
现在，也是你们书上，这是两个pz轨道,组成的成键轨道。
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All right, so we can now see a little bit of what the power of molecular orbital theory is in predicting what kind of bonds we're going to see in molecules, or whether or not we'll see this bonding occur at all.
好了，我们已经可以看到一点,分子轨道理论在预测分子中,所成的键或者分子，能不能成键方面的能力了。
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So if we name this orbital, this is an anti-bonding molecular orbital So we had bonding and now we're talking about anti-bonding.
这是反键分子轨道,我们有了成键，现在我们讨论反键。
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And to do this we're going to introduce valence bond theory, and the idea of hybridization of orbitals.
在这之前我们要引入价电子成键理论，和杂化轨道的概念。
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So we'll start to look at molecules and we'll see if we take two atoms and we fill in our molecular orbital and it turns out that they have more anti-bonding orbitals than bonding, that's -- a diatomic molecule we'll never see.
我们要看开始看一看分子,并且我们会发现如果我们,取两个原子并且填入分子轨道,结果是它们的反键轨道,比成键轨道更多，这就是-一个我们不会看到的二元子分子。
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If we think about bringing in those last two carbons, what you can see is that for every carbon, two of its hybrid orbitals are being used to bond to other carbons.
如果我们考虑引入最后两个碳原子，你会看到的是对于每个碳原子，其中的两个杂化轨道,和另外的碳原子成键。
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You have two electrons in antibonding to kind of offset the bonding.
你有两个电子,在远离成键轨道的反键轨道上。
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You might have thought before we started talking about molecular orbital theory that non-bonding was the opposite of bonding, it's not, anti-bonding is the opposite of bonding, and anti-bonding is not non-bonding.
你也许在我们讨论分子轨道之前,就想过非成键时成键的反面，它不是，反键才是成键的反面，反键不是非成键。
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So if we take a look at nitrogen here, what you'll notice is we have thre available for bonding, - and we already have our lone pair -- one of our orbitals is already filled up.
如果我们看一下氮原子，我们注意到我们可以成3个键，我们已经有一个孤对-,其中的一个轨道已经被填满了。
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So any time I draw these molecular orbitals, I do my best, and I'm not always perfect, yet trying to make this energy different exactly the same for the anti-bonding orbital being raised, versus the bonding orbital being lowered.
所以我在画这些分子轨道的时候，虽然不是很完美，但我总是尽量,让反键轨道引起的，能量升高和成键轨道。
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I want to finish this discussion by including the anti-bonding orbital, and this is a tip for you when you're drawing your molecular orbital diagrams, any time you draw a bonding orbital, there is also an anti-bonding orbital that exists.
我想要以包含反键轨道,来结束这个讨论，告诉你们一个,画分子轨道图的小技巧，任何时候你画一个成键轨道，都会存在一个反键轨道。
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So we're going to finish talking about molecular orbital theory, we'll switch over to discussing bonding in larger molecules, even larger than diatomic, so we'll move on to talking about valence bond theory and hybridization.
我们要结束关于分子轨道理论的讨论，转向讨论大分子的成键，比二原子分子更大的分子，我们会继续讨论价电子成键理论,和杂化。
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And this again is what we're going to call a bonding orbital.
同样，我们叫它成键轨道。
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Here is the antibonding and here is the bonding.
这是反键轨道，这是成键轨道。
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When you are done you have three electron pairs in bonding orbitals.
当你完成的时候,成键轨道上共有三对电子。
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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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So, let's start our discussion of a bonding orbital.
让我们开始来讨论成键轨道。
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So that's the idea of a bonding molecular orbital.
这就是成键分子轨道的概念。
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So, bonding orbitals are down here.
所以成键轨道在下面。
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And if we think about the six hydrogens, now each of those are going to bind by combining one of the carbon hybrid orbitals to a 1 s orbital of hydrogen.
如果我们考虑有六个氢原子，每个都会合起来,碳杂化轨道成键,每个氢的1s轨道。
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So you should remember that any time we combine 2 s orbitals, what we're going to find is if we constructively interfere those two orbitals, we're going to form a bonding orbital.
你们要记住，任何时候我们组合两个2s轨道，我们会发现,如果我们把它们相长叠加，我们会得到一个成键轨道。
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