Which of the following geometries for the complex ion [Co(en)(...

Question

Which of the following geometries for the complex ion [Co(en)(H₂O)₃]²⁺ are possible?

Accepted Answer

Welcome back everyone. Our next problem says, draw the structure of, we have a complex that's within brackets V and in parentheses H2O 2, then in parentheses, cat lowercase cat subscript two and then outside the brackets, we have cl. So basically, we have a counter ion of chloride and then in our brackets are complex with vanadium, two water liggons and two cat liens identify the co-ordination geometry, oxidation number and co-ordination number of V or vanadium. So let's think about what's going on here. The co ordination number will probably be the easiest, we can look at our number of ligands. But we need to remember this isn't just the number of ligands. It's the number of bonds that our metal has to the ligands. So we have four ligands total, we have two water ligands and then we have two of these cat ligands. So we need to think about the structure of cat and determine how many bonds it forms. Water, of course, is mono dentate. But when we look at cat, this is cat coate. And if we look at its structure, it has a fennel ring that has two negatively charged oxygens on adjacent to carbon atoms. So if we think about bonding as oxygens have lots of, they're very rich in electrons with three lone pairs on each one. So each of these oxygens is capable of forming a bond to our metal atom and therefore catic coate is bent. So in terms of the co ordination number, the number of bonds we're going to form are mono dentate water multiplied by two by dentate cat coate multiplied by two since there's two of them as well. So we have two bonds from the water and four bonds from the cat. So our total co ordination number for vanadium will be six even though we have just four ligands because it forms six spots. Now, we need to think about the oxidation number of an AM. So we need to look at our charges here. So we do have a counter ion which is this chloride, the charge on chloride is going to be negative one. So we know that our overall complex charge of our vanadium complex is going to be a positive one. So to figure out our oxidation state, we say that the overall charge of positive one must equal the oxidation state o period S period of vanadium plus our charge on our water ligands, which is zero. So we don't need to multiply since it's neutral and then our charge on our cat ligaments. Well, looking at our cat coate ligands, you can see it has a charge of negative 21, negative charge on each oxygen. So we have a charge of negative two, multiplied by two of those cat ligands. So we have positive one, we'll equal the oxidation state of an aum minus four. And so the oxidation state of vanadium will equal positive one plus four, it will be positive five. So our oxidation number will be positive five. So now we've got two pieces of information. We still need the co-ordination geometry and our structure. Well, our co-ordination number is six. So we know we'll have an octahedral arrangement. So our co ordination geometry and let's draw a generic octal complex with vanadium in the middle. We'd have one ligand going up and one down. And then we're going to have this square planar middle part which will have two atoms projecting behind the screen and drawn with dash lines and then two or two ligands, I should say two ligands projecting out from the screen towards a viewer which are the sort of wedges. So first, we would want to use our b dentate ligand since that will have the more complicated bonding. And then we fill in our Monod ligands after that, while these two oxygens are in adjacent carbons, so it makes most sense to put them as adjacent bonds to the vanadium. So there is one of our cholate. So I'll put that on the left side of vanadium, draw its fennel ring there and then we'll just put the other one on the opposite side and drawn another fennel ring. Now we just have the spots on top and bottom open or our water ligands, which of course bond on the oxygen atom. So 02 on the top 02 on the bottom. Now, we need do need to think about, do we have any optic isomers? But our molecule here has a plane of symmetry. So it's a Cairo and therefore won't have any an anim. So now we just need to remember that this whole structure here, a whole complex has a charge of positive one. So put a plus there and then put in our counter ion chloride minus. So now we've got our whole structure with our two cat ligands on opposite sides from each other and then the two water ligands opposite from each other. Our co-ordination number is six oxidation number positive five and co ordination geometry octahedral for our vanadium at up. See you in the next video.

Struggling with General Chemistry?

Which of the following geometries for the complex ion [Co(en)(H₂O)₃]²⁺ are possible?

Watch next

Coordination Numbers & Geometry practice set

Struggling with General Chemistry?

Which of the following geometries for the complex ion [Co(en)(H2O)3]2+ are possible?

Watch next

Coordination Numbers & Geometry practice set

Which of the following geometries for the complex ion [Co(en)(H₂O)₃]²⁺ are possible?