Frequently Asked Question

To calculate the theoretical magnetic moment of [Co(ox)3]4-, you would use the spin-only magnetic moment formula: μ = √(n(n+2)) BM, where n is the number of unpaired electrons. First, determine the oxidation state of cobalt. Since oxalate (ox) has a -2 charge and there are three of them, the total charge from the ligands is -6. To balance the overall -4 charge of the complex, cobalt must be in the +2 oxidation state. The electronic configuration of Co2+ is [Ar] 3d7. In the octahedral complex [Co(ox)3]4-, the d electrons will be arranged according to crystal field theory. Since oxalate is a weak field ligand, the d electrons will be distributed in a high spin configuration. Therefore, there will be 3 unpaired electrons in the d orbitals of cobalt. Plugging this into the spin-only magnetic moment formula, we get μ = √(3(3+2)) BM = √15 BM = 3.87 BM.