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 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。
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。
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。
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。
So you can see that this is non-bonding, this is even worse than non-bonding, it's anti-bonding, because we're actually getting rid of electron density between the two nuclei.
所以你可以看到这是不成键的,它甚至比不成键还糟糕,它是反键,因为我们实际上是去掉了,两个原子核之间的电子。
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。
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。
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。
So what we'll have here is a trigonal planar case, and you can see that we only have three electrons that are set for bonding, so we'll add three hydrogens, and for b h 3, we'll get a stable structure here.
让电子劲量远离的时候,不用考虑它,这个例子是平面三角形,你可以看到,只有3个电子可以成键。
So you can see that polar covalency is a tendency towards ionic bonding.
所以你看得出极性共价就是,趋向离子键的。
We can also talk about anti-bonding orbitals where we have destructive interference.
我们也可以讨论,相消干涉的反键轨道。
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。
We can do our 4 bonding electrons.
这是4个成键电子。
So that's going to be the end of the exam 1 material, and then we'll move on to exam 2 material, which is kind of exciting, because we've been talking about just individual atoms and ions up to this point, and now we can talk about molecules, so we're going to start talking about bonding.
到此为止就是第一次考试的内容,接下来我们会开始讲第二次考试的内容,这些内容令人有点兴奋,因为我们一直都只是在讨论单个的原子,和离子到目前为止,而现在我们可以讨论分子了,要开始讨论成键的问题了。
So, if we think about this z bonding axis between the two carbon atoms, we can picture overlap of those s p hybrid orbitals, and then we can also picture bonding to hydrogen.
如果我们考虑,两个碳原子之间的z成键轴,我们可以画出sp杂化轨道的交叠,我们也可以画出和氢原子的成键。
So if we still have an angle of a 109 . 5 degrees, and again, we still have four unpaired electrons available for bonding, we can make one of those bonds with another s p 3 hybridized carbon, so we're going to make up one pair here.
如果键角仍然是109。,同样,我们还有4个未配对的电子可以用来成键,我们可以用其中的一个,和另外一个sp3杂化碳原子成键,这样我们可以组成一对。
So we end up with 3 s p 2 hybrid orbitals, so we can think about what would happen here in terms of bonding, and if we think about how to get our bonds as far away as possible from each other, what we're going to have is the trigonal planer situation.
因为现在sp2轨道有1/3的s特征,2/3的p特征,而不是3/4。,我们最后得到3个sp2杂化轨道,我们可以想象,成键时会发生什么,如果我们考虑。
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