In order to explain the bonding, the 2s orbital and two of the 2p orbitals called sp 2 hybrids hybridize; one empty p-orbital remains. Ethene C 2 H 4 has a double bond between the carbons. In this case, carbon will sp 2 hybridize; in sp 2 hybridization, the 2s orbital mixes with only two of the three available 2p orbitals, forming a total of three sp hybrid orbitals with one p-orbital remaining.
The three hybridized orbitals explain the three sigma bonds that each carbon forms. The two carbon atoms form a sigma bond in the molecule by overlapping two sp 2 orbitals. The pi bond between the carbon atoms perpendicular to the molecular plane is formed by 2p—2p overlap.
That's the small lobe, and then that's the big lobe like that. A sigma bond is one where there's an overlap kind of in the direction in which the lobes are pointed. And you might say, well, how can there be any other type of bond than that? Well, the other type of bond, so this right here-- let me make this clear. This right here is a sigma bond. And you say, well, what other kind of bond could there be where my two orbitals overlap kind of in the direction that they're pointing?
And the other type of bond you could have, you can imagine if you have two p orbitals. So let me draw the nucleus of two atoms, and I'll just draw one of each of their p orbitals.
So let's say that that's the nucleus and I'll just draw their p orbitals. So a p orbital is just that dumbbell shape. Let me draw them a little bit closer together. So a p orbital is that dumbbell shape. So let me draw this guy's-- one of his p orbitals.
I want to draw it a little bit bigger than that, and you'll see why a second. So one of his p orbitals right there. It comes out like that. And then this guy over here also has a p orbital that is parallel to this p orbital, so it goes like that.
Let me draw that other one a little bit straighter. It goes-- I want it to overlap more, so it goes like that. I think you get the idea. So here, our two p orbitals are parallel to each other.
This, you can imagine, these are sp3 hybridized orbitals. They're pointing at each other. Here, they're parallel. And this is a pi bond. Let me make this clear.
And this is one pi bond. So you could call it a pi, literally, with the Greek letter pi: pi bond. Sometimes you'll see this just written as pi bond. And it's called a pi bond because it's the Greek letter for essentially p, and we're dealing with p orbitals overlapping. Now sigma bonds, which are what form when you have a single bond, these are stronger than pi bonds; pi bonds come into play once you start forming double or triple bonds on top of a sigma bond.
To kind of get a better visualization of how that might work, let's think about ethene. So it's molecular structure looks like this. So you have C double-bonded to C, and then each of those guys have two hydrogens. So let me draw what it would look like, or our best visual, or our best ability to kind of conceptualize what the orbitals around the carbon might look like.
So first I'll draw the sp2 hybridized orbitals. So let me just make it very clear what's going on here. So when we were dealing with methane, which is literally just a carbon bonded to four hydrogens, and if I actually wanted to draw it in a way that it kind of looks a little three-dimensional with a tetrahedral structure, it might look like this.
This hydrogen is pointing out a little bit. This hydrogen is kind of in the plane of the page, and then maybe that hydrogen is behind it, and then you have one hydrogen popping up. That's methane.
And we saw that these were all sp3 hybridized orbitals around the carbon, and then they each formed sigma bonds with each of the hydrogens. We saw that in the last video. And when we drew its electron configuration, in order for this to happen, carbon's electron configuration when bonding in methane needed to look like this. It needed to look like 1s2. And then instead of having 2s2 and then 2p2, what you essentially have is-- let me try it this way, actually, even better.
Let me write this better. In 1s, you had two electrons, and then instead of two s's, you had two electrons and on each of the p's, you had one, the s's and the p's all got mixed up and you had a 2sp3 hybridized orbital, another 2sp3 hybridized orbital, another 2sp3 hybridized orbital, and then another one, sp3.
Normally, when carbon's sitting by itself, you would expect a 2s here, and then you'd have a 2p in the x-direction, a 2p in the y-direction, and then a 2p in the z-direction. When you're dealing with the carbons in ethene, remember, eth- is for two carbons and ene-, because we're dealing with an alkene. We have a double bond here. In this situation, the carbon's electron configuration when they bond in ethene looks more like this. So you have your 1s, and the 1s orbital is still completely full.
It has two electrons in it. But then in your 2 shell, I'll just write-- let me do this in a different color. So in our 2 shell, I'll show you what I mean in a second. So, guys, the only one that has more than one pie bond here is number three.
Begin typing your search term above and press enter to search. Press ESC to cancel. Skip to content Home Physics What is sp2 hybridisation? Ben Davis February 26, What is sp2 hybridisation? How many pi bonds can sp2? Does sp3 have a pi bond? Is a triple bond 2 pi bonds?
Can sp3d form pi bonds? Are all double bonds pi bonds? Why are pi bonds called pi bonds? Is C bond double bond OA? What is C double bond called? Can pi bonds exist without sigma bond? Are pi bonds hybridized? Are sigma bonds stronger than pi bonds? Why hybridization is only for sigma bond?
Are pi bonds always p orbitals? Are lone pairs sigma or pi bonds? How many pi bonds are in SP? Why are pi bonds not symmetrical? What is a sigma and pi bond?
0コメント