So we can have four total hydrogens bonding here, - and we can think about how to describe these carbon- carbon bonds.
我们这里一共有四个氢原子成键,我们可以考虑怎么来-,描述碳碳键。
So what we end up with in terms of our bonding electrons is going to be 6 bonding electrons.
因此最终我们需要六个成键电子,那么我们可以来把它们填上。
OK, so what we've gone through today is we've introduced covalent bonding, and we've figured out a way to quantify it.
好的,那么我们已经经历了,是我们已经介绍了共价键,我们已经想出了一种定量的方法来。
There's not actually chemical covalent bonds that are formed but it's a non-covalent interaction, usually dominated by hydrogen bonding.
所以配体和受体之间不生成共价键,这是一种非共价化合反应,它们通常以氢键相联
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。
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。
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。
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。
All right, so the bonding order, you're correct, should be 2, if we subtract the number of bonding minus anti-bonding electrons and take that in 1/2.
好,你们是对的,键序为,如果我们用成键数,减去反键数除以2。
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。
Because, when you ask yourself that question, you should consider what is the thermal energy versus the bonding energy?
这是因为,对于这个问题,我们应当考虑到,什么样的热能,对应于键能?
So let's see, we started with 8 bonding electrons, and we used up only 4, so the answer is yes, we have 4 bonding electrons left.
那么让我们来看看,我们一开始有八个成键电子,然后只用掉了四个,因此答案应该是还有剩余,我们还剩下了四个成键电子。
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。
If these bonds were all completely of equal distance apart, whether is was a lone pair or bonding electrons, 5° the angles would be 109 . 5 degrees.
如果不管它是孤对,还是成键,它们等距分开的话,键角是109。
If the bonding energy is very strongly negative, thermal energy isn't great enough to disrupt those bonds and allow those bonds to be broken and then have fluidity.
如果键能非常强,热能并不足以,打破这些化学键,破坏这些化学键,并使它们液化。
However, on Friday we will use a different approach so we can talkabout bonding within atoms that have more than two atoms, molecules with more than two atoms.
但是,在周五我们,会用一种新的办法来讨论,不止两个原子的分子的成键。
We have one, two, we have four bonding domains.
我们发现一共生成了1,2,3,4根键。
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。
And this will become more and more clear as we actually talk about these reactions and talk about bonding.
而这将会变得越来越清楚,在我们讨论这些反应以及讨论成键的过程中。
Yeah, so also 4. We started with 10 valence electrons, we used up 6 of those as bonding electrons, so we have 4 left, which will be lone pair electrons.
对,也是四个,我们从十个价电子开始,只用了六个来成键,因此我们还剩下四个,它们将成为孤对电子。
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。
So, for starters we'll keep that as our zero energy, we're going to change it soon to make something that makes more sense in terms of bonding, but we'll keep that as zero for now.
因此,首先我们将会保持零点能的这个定义,但很快我们就会对它进行修改,使它在讨论成键时更合理,但是目前我们还是暂时采用这种定义。
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。
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。
I'm an organic chemist, so I love carbon, it's one of my favorite atoms to talk about, but it would be nice to get to the point of bonding and even reactions to talk about all the exciting things we can think about once we're at that point.
我是个有机化学家,我喜欢碳原子,这是我最喜欢谈论的原子之一,但我更喜欢讲成键,甚至化学反应的概念,一旦到了这之后,我们就可以考虑各种激动人心的事情。
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。
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。
You can see that there is no value in studying inner shell electrons to ask questions about bonding.
你应该了解考虑成键时,去考虑内层电子,是毫无意义的。
So we have 18 electrons, and the next thing that we need to figure out is how many bonding electrons we have.
那么我们有十八个电子,下一步要做的是判断,我们有多少个成键电子。
Remember, that's going to become important when we talk about bonding, we don't need to worry about it too much right now.
记住,这在我们讨论到,成键的时候很重要,现在你们还不用太多的考虑它。
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