 Hello, this is Professor Nesheba, and I wanted to do a little follow-up video on examining the transition middle cation complexes. So here's the handout that we were looking at, and the idea here is here's some bare d-orbitals, and they have these these shapes, and when it gets put into a complex, then you can still recognize those those shapes. So for example, I have here the chromium-carbon monoxide complex, and you can you can kind of see that same d-orbital in there. But now it's surrounded by these ligands, and the next thing I just want to point out here is that there's a couple of these over here I'm looking at. There's a pair, so these must be the EG antibonding orbitals, and we'd like to see whether these interactions here are sigma star or pi star, and I kind of think that in going from the metal, which is here to the ligand, it looks like it has symmetry about the internuclear axis, and it obviously has a color change, phase change, and so this is a sigma star kind of interaction here. So we would say these EG guys here are sigma star, both of them. How about down here on the set of three, the T2Gs? Well, this one it kind of looks like, well, there's obviously the d-orbital of the metal, and there's just not very much interaction going on with respect to that ligand there, so we would call that one an N for a non-bonding interaction. I'm just pointing that out because here if we go into the chromium water complex and I'll do the same thing here. You can kind of see, so I'm now once again at the EG orbitals. I can see that kind of a d-orbital there in the around the metal. There's once again a sigma star going on with respect to the ligands, and on both of them, and as you can see, but now if I drop down to these T2G guys there, now I can see this really significant anti-bonding interaction going on between that metal-centered d-orbital and, for example, that ligand right there, and since there's a color change, but it doesn't have symmetry about the inter-nuclear axis, that must be pi star, and if you look at all three of these guys, you'll see that there's, you can identify pi star interactions all across the board. Okay, and now if we go over to the ammonia complex and and think about the same sort of thing there. Well, once again, I'm here at the EG pair of orbitals, and that looks like a d-orbital right there in the middle, and I've got something that looks like a sigma star interacting with the ligands. If I drop down now to the the T2Gs, well, this is a pretty extreme example, right? I see definitely a d-orbital there and hardly anything going on with the ligand, so this is definitely a case of a non-bonding interaction of the d's with the ligands. Oh, and there's one more point about this. If I'm interested in the energy gap between the T2Gs and the EGs, what you do is you click on the higher one there, and you can see down here that energy is minus 14.9, and if I go down, that's the crystal field splitting right there, and so I go down to there, and now I see that the new energy is minus 21.4, so it's the difference between those two numbers that give you the crystal field splitting delta, delta naught.