Cobalt(III) trifluoroacetylacetonate, Co1tfac23, is a sixcoordinate, octahedral metal chelate in which three planar, bidentate tfac ligands are attached to a central Co atom:

(d) Draw a crystal field energy-level diagram for Co1tfac23, and predict its magnetic properties. (In this complex, tfac is a strong-field ligand.)

Video transcript

All right. Hi everyone. So this question says that tris 110 frale ion three, it is an octahedral complex with three bate fe ligands surrounding the central metal atom. Note bean is a neutral strong field ligand. What is the crystal field energy level diagram or tris 110 Fline iron three? Is it paramagnetic or diamagnetic? Now recall that the crystal field theory is a theory that attempts to explain the bonding observed in complexes by explaining the electrostatic interactions present in the complex. Now, the crystal field theory makes a point of examining the influence of ligands present in the complex as well as the energy is of the D orbitals with respect to the central Meadow ale. So because of this right, the central metal atom which happen to be iron is going to be observed in more detail for this question because the question is how many D electrons does iron have in this specific complex. So our first step is to determine the oxidation state of iron. Now recall that the charge of the complex is equal to the total oxidation number of the complex. And so the sum of the oxidation numbers of the metal and all ligands must equal the total oxidation number. So if I take the oxidation state of iron and treat this as X, then X added to the oxidation state of the feed ligand multiplied by the quantity of the fee ligands should be equal to positive three, which is the overall charge and therefore the overall oxidation number of the complex. So it just so happens that fen like the question mentions is a neutral ligand, which means that the oxidation state is going to be zero. So X added to zero, multiplied by three equals negative three, which means that X is equal to positive three. So now to determine the number of the electrons, we have to find the electronic configuration of iron three positive. So first, we'll start off with the electronic configuration of neutral iron recall that when an atom is neutral, the number of electrons is equal to the number of protons, which is given by the atomic number, right. So if iron has an atomic number of 26 which it does as a neutral atom, it should have 26 electrons which gives rise to an electronic configuration of argon or S two 3d 6. So now this is neutral iron, right, in order to find the electronic configuration of iron three positive, because the charge is positive electrons are going to have to be removed from the highest energy levels. So because three electrons have to be removed in this case, two will be removed from the four s orbital first followed by one from the 3d orbital. This gives rise to an electronic configuration of Oregon 3d 5. So now we know that there are five D electrons to be distributed among the D orbitals in the energy level diagram. Right. So recall it for an octahedral complex, there are 3d orbitals in the lower energy level and two in the higher energy level. So the lower energy orbitals, RDXYDXZ and DYZ respectively, whereas the higher energy orbitals are DZ squared and DX squared subtracted by Y squared. So now because Finn is a strong field and low spin ligand, the splitting energy of this complex is going to be quite large. So when it comes to distributing the five D electrons, right recall that lower energy orbitals have to be filmed first. And if there are multiple orbitals in the same energy level, they all have to contain unpaired electrons before those electrons can subsequently be paired. Right? So in this case, I have five D electrons which I will first distribute among the three lower energy orbitals. This means that each lower energy D orbital is going to have one paired electron that accounts for three, which means that the remaining two are going to be paired with the first three or with two of the first three I should say. So now here is the crystal field energy level diagram, but we now have to distinguish between paramagnetic and diamagnetic complexes recall that a paramagnetic complex has at least one unpaired electrons, whereas a diamagnetic complex as no unpaired electrons. So based on the energy level diagram that we drew previously, the orbital dyz has one unpaired electron, which means at the complex is paramagnetic, right, because it does have at least one unpaired electron and there you have it. So here is our final answer right. The crystal field energy level diagram or tris 110 Fline iron three is shown here on the screen and it is in fact paramagnetic because it does have at least one unpaired electron. So with all that being said, thank you so very much for watching and I hope we found this helpful.