Well, if this bond has completely identically equal sharing of electrons, then this bond will be nonpolar.
如果一根键连的两个原子,对键上的电子吸引程度是完全等价的,那么这根键是非极性的。
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。
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。
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。
So it's trigonal because we have these three atoms that are bound to the central atom here, and if you picture it, it's actually shaped like a pyramid.
这里三角形是因为,我们有3个原子核中心原子成键,如果你画它,它就是金字塔形的。
There's absolutely no reason I couldn't have switched it around and said that instead the pi orbitals form between these atoms instead of those first atoms I showed.
我完全没有理由,不能把它转过来,现在π键在这些原子间,而不是我开始展示的那些原子间。
Whereas in molecular orbital theory, what I'm telling you is instead we understand that the electrons are spread all over the molecule, they're not just associated with a single atom or a single bond.
而在分子轨道理论里,我要告诉你们的时,我们任为电子分布在整个分子中,它们不仅仅是和,一个原子或者一个键有关。
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。
When it gets to thousands of atoms things start to condense because there is a capacity to form other bonds secondarily, which we will get to in a little bit.
当有成千上万的原子,开始浓缩,因为形成次级键,的趋势,然后得到的体积只有一点点。
And we know that it's electron density between the nuclei that holds two atoms together in a bond.
我们知道是两个原子核之间的,电子密度保持两个原子在一起成键的。
then what you have is a carbon in the middle with three hydrogens around it, and then it can only be bonded to one other thing.
那么你就会有一个碳原子在中心,三个氢原子围绕着它,那么它只能再和一个原子成键。
There's absolutely nothing that tells us which atoms we should put it between, because they're both oxygen-oxygen.
我们没有任何理由把它们,放在其中一对原子中间,因为它们都是氧氧键。
So if I try to rotate my 2 atoms, you see that I have to break that pi bond, because they need to be lined up so that the electron density can overlap.
如果我要试着转动两个原子,你会看到我必须要打破一个π键,因为他们需要连接起来,让那些电子能够重叠。
CH4 is sp3 carbon hybridization.
能容纳4个原子成键。
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。
So let's take the case of acetylene where we have two carbon atoms that are going to be triple bonded to each other, each are bonded to a carbon and then to one hydrogen.
让我们来看一看乙炔的例子,我们有两个碳原子,成三键,每个碳和一个碳一个氢相连。
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, for instance, this would suggest to us by the way it's written that the hydrogen is attached to the nitrogen and not the oxygen.
因此,比如,这样的写法会提醒我们,这个氢原子是与氮原子成键的,而不是氧。
Then we're going to actually use MO theory to describe bonding within these molecules, and we'll start with homonuclear diatomic molecules.
然后我们要利用MO理论,来描述这些分子内的成键,我们要讨论同核双原子分子。
So, in fact, yes, we did confirm that these covalent bond, at least in the case of hydrogen, we have confirmed by the numbers that we are at a lower energy state when we talk about the bonded atom versus the individual atom.
因此,事实上,是的,我们证实了共价键,至少在氢这种情况下,我们通过数据证实了,成键的原子处于能量更低的状态,当其与单个的原子相对比时。
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。
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。
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。
So again, if we think about that shape of that carbon atom, it's going to be trigonal planar, 120° it's going to have bond angles of 120 degrees, because we have this set up of having three hybrid orbitals.
如果我们考虑碳原子的形状,它是平面三角形,键角是,因为我们有这三个杂化轨道。
It's what it's called when an atom takes both electrons in the bond.
这就是它为什么叫这个名字,当一个原子从成键中得到两个电子。
By terminal I mean they're only bonded to one thing.
我所说的末端的意思是它们只能与一个原子成键。
Three unpaired electrons in nitrogen.
有三个未成键电子在氮原子中。
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。
All right, so the type of bond energies that we can go and look up in tables are individual atom bonds, H-H, F-F, and the like.
好的,键能的类型,我们能够在表中查到,都是独立的原子键,H-H,F-F以及类似的。
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。
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