Answer to Question #74398 in Inorganic Chemistry for Sayantan Bhanja

Question

How to show the splitting of d orbitals for molecules having CUBIC geometry like Caesium Chloride? Please explain the mechanism in details. Giving proper explanation and steps. Thank you

Answer 1

In a cubic field, 8 ligands; the splitting of d-terms will be analogous to the tetrahedral, but the numerical value of splitting in the cubic field is greater than in the tetrahedral one. The reason for this is that the cubic symmetry of the placement of the ligands is the limiting case of the tetrahedral, therefore the transition from the tetrahedron to the cube is due only to the already existing splitting effect. In subgroups of d-elements in the transition from 4 to 5, especially the 6th period of D, of the same type of complexes increases significantly. This is due to the fact that 4d and 5d - orbitals propagate in space far from the core than the 3d - orbital. This corresponds to a stronger repulsion of electrons and ligands and, accordingly, a greater split of 4d and 5d levels compared to the 3d level. Therefore complexes of 4d and 5d electrons are low spin.