Chemical Bonding: C₆H_{12/sub> Lewis Structure}

Drawing the Lewis Structures for C₆H₁₂

Transcript: In this video, we're going to look at the Lewis structure for C6H12. C6H12 has a total of 36 valence electrons. There are a number of different ways you can draw the Lewis structure for C6H12. I believe there are 16 of them. If you want to look them up on Google, just type in "C6H12 Isomers" and you should find more information. We're going to look at cyclohexane. So for cyclohexane, "cyclo" means we're going to have a ring. "Hex", that's six: we have six Carbons. And "ane" means it's going to be an alkane. That means we'll have only single bonds.

So let's put a structure on the screen that's a ring, has six Carbons, and only single bonds. You can see that each Carbon has two bonds connected to it. Each bond is two valence electrons. So each Carbon has four valence electrons right now. They need eight to have a full outer shell. We need to put these 12 Hydrogens around, so we're going to put two Hydrogens on each Carbon. So now we've added in all 12 Hydrogens around these six Carbons, and you can see that each Carbon has four bonds. So each Carbon has eight valence electrons. They have octets, so their outer shells are full. Each Hydrogen has a bond, which is two valence electrons, and that's all they need for a full outer shell.

So this is the Lewis structure for cyclohexane, C6H12. It's two-dimensional, though; it's very flat here. If we were to look at the three-dimensional structure, if we looked at it in three dimensions, it would actually look quite different than it did on paper. Here, the whites are the Hydrogens and the blacks are the Carbons. This is called the cyclohexane chair conformation. It can also take the form of something called the cyclohexane boat conformation that looks like this. So it has a little bit different shape to it, three dimensional shape. Of course, they're always moving and changing around, so it's not a static picture as we've portrayed here.

So that's the Lewis structure for C6H12, cyclohexane. This is Dr. B., and thanks for watching.