Frequently Asked Question

To determine the theoretical magnetic moment of [Co(ox)3]4-, we need to consider the following:
1. Oxidation State of Cobalt: In [Co(ox)3]4-, the oxidation state of cobalt is +2. This is because oxalate (ox) has a -2 charge, and there are three of them, giving a total charge of -6. To balance the overall charge of 4-, the cobalt must have a +2 charge.
2. Electronic Configuration: The electronic configuration of Co2+ is [Ar] 3d7. In an octahedral complex like [Co(ox)3]4-, the d orbitals split into two sets: eg (dxy, dxz, dyz) and t2g (dz2, dx2-y2).
3. Crystal Field Splitting: The oxalate ligand is a weak field ligand, leading to a small crystal field splitting. This means that the energy difference between the eg and t2g orbitals is small, and the electrons will fill the t2g orbitals before pairing in the eg orbitals.
4. Spin-Only Magnetic Moment: The spin-only magnetic moment is calculated using the formula μs = √n(n+2) BM, where n is the number of unpaired electrons. In the case of [Co(ox)3]4-, there are 3 unpaired electrons in the t2g orbitals. Therefore, the theoretical spin-only magnetic moment is μs = √3(3+2) BM = √15 BM ≈ 3.87 BM.
Conclusion: The theoretical magnetic moment for [Co(ox)3]4- should be approximately 3.87 Bohr magnetons (BM), based on the spin-only magnetic moment calculation.