Frequently Asked Question

To calculate the theoretical magnetic moment of [Co(ox)3]4-, you would use the spin-only magnetic moment formula: μs = √n(n+2) BM, where n is the number of unpaired electrons. First, determine the oxidation state of cobalt in the complex. Since oxalate (ox) has a -2 charge, and there are three oxalate ligands, the overall charge from the ligands is -6. The complex has a -4 charge, so cobalt must be in a +2 oxidation state. Then, determine the electronic configuration of Co2+ (d7). In an octahedral complex, the d orbitals split into two sets, with the lower energy set (t2g) filled first. Since there are three oxalate ligands, which are weak field ligands, the electrons will fill the t2g orbitals before pairing up. This gives us 3 unpaired electrons. Therefore, the theoretical spin-only magnetic moment would be calculated as: μs = √3(3+2) BM = √15 BM ≈ 3.87 BM.