px So we're talking about pi carbon 2 p x, 2px because it's the x axes combining to carbon 2 p x.

我们讨论的是π碳，因为它在x轴结合成碳。

麻省理工公开课 - 化学原理课程节选

px 2py So we need to fill all the way up to the pi 2 p x, and the pi 2 p y.

我们需要填到。

麻省理工公开课 - 化学原理课程节选

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

px We'll call it either pi 2 p x, 2py if we're combining the x orbitals, or pi 2 p y.

我们叫它π,如果是x轨道组合的话，或者π

麻省理工公开课 - 化学原理课程节选

Remember, we didn't hybridize the 2 p y orbital, so that's what we have left over to form these pi bonds.

记住，我们并没有杂化2py轨道，这是我们剩下的那个行成了π键。

麻省理工公开课 - 化学原理课程节选

Again, we're going to take the linear combination of those p atomic orbitals and make what are called pi or some more sigma molecular orbitals.

同样的，我们需要得到,原子p轨道的线性组合,然后组成我们所说的,π分子轨道或者sigma分子轨道。

麻省理工公开课 - 化学原理课程节选

So, what we end up having is three of these pi -- 2 p y 2 p y bonds, we can have one between these two carbons here.

我们剩下的有三个π键-,2py2py键，在这两个碳原子之间会有一个。

麻省理工公开课 - 化学原理课程节选

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。

麻省理工公开课 - 化学原理课程节选

What about this second bond here sigma where we're going to have interaction of 2 p orbitals, is that sigma or pi?

那2p轨道相互作用的第二个键呢,它是，还是π？

麻省理工公开课 - 化学原理课程节选

And the pi star orbitals result from any time you have destructive py interference from 2 p orbitals that are either the p x or the p y.

星轨道是由于2p轨道的相消干涉,不管是px还是。

麻省理工公开课 - 化学原理课程节选

You can see that we have two unpaired electrons in this molecule here one in the pi 2 p x star, and one in the pi 2 p y star orbital.

你们可以看到我们这个,分子力有两个未配对电子,一个在π2px星，一个在π2py星轨道。

麻省理工公开课 - 化学原理课程节选

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。

麻省理工公开课 - 化学原理课程节选

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。

麻省理工公开课 - 化学原理课程节选

So some p orbitals form pi molecular orbitals, and some form sigma p orbitals.

有些p轨道会形成π分子轨道，有些会形成p轨道。

麻省理工公开课 - 化学原理课程节选

So we're going to call this the sigma 2 p x star, or if we're talking about the 2 p y orbitals we'll call this the pi 2 p x star, and the pi 2 p y star.

我们叫这个sigma2px星，或者如果我们说的是π2py轨道的话,我们叫这个2px星，这个π2py星。

麻省理工公开课 - 化学原理课程节选

And what we see here is now when we're combining the p, we have our 2 p x and our 2 p y orbitals that are lower in energy, and then our pi anti-bonding orbitals that are higher in energy.

这里我们看到,当我们结合p轨道时，在低能处我们有,2px和2py轨道，π反键轨道在更高的能级处。

麻省理工公开课 - 化学原理课程节选

So it already should make sense why we have that p orbital there, in order to form a pi bond, we're going to need a p orbital.

这里有p轨道是很合理的,为什么我们在这里有P轨道，为了形成一个π键，我们需要一个p轨道。

麻省理工公开课 - 化学原理课程节选

py So this will be pi carbon 2 p y, carbon 2 p y.

这是π碳2py碳。

麻省理工公开课 - 化学原理课程节选

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。

麻省理工公开课 - 化学原理课程节选

There's not two bonds, that's one pi bond, and the reason is because it's 2 p orbitals coming together, and remember p orbitals have electron density above and below the axis, so when they come together, it kind of looks like one bonds, but essentially what we have here is one pi bond.

这不是两个键，这是一个π键，因为这是两个2p轨道组合而成的，记住p轨道在键轴之上,和键轴之下都有电子密度，当它们靠近时，这看着很像两个键，但本质上它是一个π键。

麻省理工公开课 - 化学原理课程节选

And again, this is between the p orbitals, these are not hybrid orbitals, so when we name this bond we're going to name it as a pi bond here, because it's between two p orbitals, and it's going to be between the carbon 2 p y orbital, and the other carbon 2 p y orbital.

同样，这是在p轨道之间的，它们不是杂化轨道，所以当我们命名这个键时,我们要命名它为π键，因为它在两个p轨道之间，而且是在碳2py轨道，和另一个碳2py轨道之间。

麻省理工公开课 - 化学原理课程节选

So that's two of our types of bonds in benzene, and we have one type left, that's going to actually be the double bond or the pi bond that So we can have one bond here between this carbon's p orbital and this carbon's p orbital.

这就是苯环里的两种键，我们还剩一种，那就是这些p轨道之间，形成的双键或者π键,我们可以在这个碳的p轨道,和这个碳的p轨道之间有个键。

麻省理工公开课 - 化学原理课程节选

All right, so what we see here is we have our sigma bond that's along the internuclear axis here, but we also have a pi bond, because each of these atoms now has electrons in it's in a p orbital, so we're going to overlap of electron density above and below the bond.

这里我们看到sigma键,是沿着核间轴的，但我们还有一个π键，因为每个原子的p轨道上,都有电子，所以电子密度在键的上面,和下面都有电子密度交叠。

麻省理工公开课 - 化学原理课程节选