So any time you have two atoms bonding, the bond axis is just the axis that they're bonding along.

任何时候如果你有两个原子成键，键轴就是它们成键的方向。

麻省理工公开课 - 化学原理课程节选

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。

麻省理工公开课 - 固态化学导论课程节选

The way that we can figure this out is using something called bond order, and bond order is equal to 1/2 times the number of bonding electrons, minus the number of anti-bonding electrons.

我们可以用叫做,键序的概念来弄明白它，键序等于1/2乘以成键电子,数目减去反键电子数目。

麻省理工公开课 - 化学原理课程节选

Clearly, we put 2 for each bond, and now we end up having 2 remaining bonding electrons left.

显然，我们在每个键处放上两个电子，那么最后我们还剩下两个成键电子。

麻省理工公开课 - 化学原理课程节选

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。

麻省理工公开课 - 化学原理课程节选

We see three bonding pairs so this is a triple bond, indeed a multiple bond.

我们看到3对成键电子所以这是一个三重键，它确实是多重键。

麻省理工公开课 - 固态化学导论课程节选

So we know that it's 1, because we have 1, 2, 3, 4 bonding, minus 2 anti-bonding, and 1/2 of that is a bond order of 1.

我们知道它是，因为我们有1，2，3，4个成键，减去2个反键，它的一半就是键序为1。

麻省理工公开课 - 化学原理课程节选

Because step five is that we need to fill in our bonding electrons, and we start it with filling in two electrons per bond.

因为第五步要做的是将我们的成键电子填在这，所以我们开始在每个键处填上两个电子。

麻省理工公开课 - 化学原理课程节选

/2 So this would mean the bond order is equal to 1/2, and in terms of valence electrons, how many bonding valence electrons do we have?

这意味着键序等于，对于价电子，有多少个成键价电子？

麻省理工公开课 - 化学原理课程节选

So for the bond order we want to take 1/2 of the total number of bonding electrons, so that's going to be 4 minus anti-bonding is 4, so we end up getting a bond order that's equal to 0.

键序等于1/2乘以,总的成键电子数，也就是4，减去反键电子数，也就是4。,所以最后得到键序为0。

麻省理工公开课 - 化学原理课程节选

And obviously, no bond is the weakest of all is not bonding.

显然，没成键是最弱的。

麻省理工公开课 - 化学原理课程节选

So, we're going to start with talking about bonding, and any time we have a chemical bond, basically what we're talking about is having two atoms where the arrangement of their nuclei and their electrons are such that the bonded atoms results in a lower energythan for the separate atoms.

那么，下面我们将从成键开始讲起，无论什么时候我们有一个化学键，基本上我们所讨论的,都是如何安排两个原子的原子核的位置,与电子的位置使得成键的两个原子,最终比分开时的能量更低。

麻省理工公开课 - 化学原理课程节选

So in terms of the carbon hydrogen bond, it's a sigma bond, - because we define it -- any time we are bonding to an atom, we have to keep redefining our bond axis to whatever two atoms we're talking about.

对于碳氢键，它是sigma键，因为我们定义它-,任何时候我们有原子成键，我们要重新定义键轴方向,为我们所讨论的两个原子方向。

麻省理工公开课 - 化学原理课程节选