Oxalates in food have been linked to a number of health issues, including hypercalcemia and kidney stone formation. What is the crystal field energy-level diagram for [Co(C₂O₄)₃]³⁻? How many unpaired electrons does it have? Noted: Oxalate is a bidentate weak-field ligand.

Among the given complexes below, predict which will be paramagnetic.

i. [Cr(NH₃)₆]²⁺

ii. [NiCl₆]^4–

iii. [Pd(NH₃)₆]⁴⁺

iv. [Cd(CN)₄]^2– (tetrahedral)

Consider the complexes given below. Identify which are diamagnetic.

i. [Zn(H₂O)₄]²⁺ (tetrahedral)

ii. [Rh(NH₃)₆]³⁺

iii. [Pt(CN)₄]^2– (square planar)

iv. [PdBr₆]^2–

For the coordination compound [Mn(en)(NH₃)₄]Br₂:

i. Provide the name of the compound.

ii. Calculate the oxidation number of Mn.

iii. Sketch its crystal field energy-level diagram.

iv. Classify the complex as either high-spin or low-spin.

v. Identify the number of unpaired electrons, if any.

The spin-only magnetic moment of a transition metal complex in Bohr magnetons (BM) is calculated as $\sqrt{n(n+2)}$ , where n is the number of unpaired electrons. It is proportional to the amount of paramagnetism in the metal. What is the spin-only magnetic moment of Mn³⁺, a first-series transition metal, when it forms an octahedral complex with strong and weak field ligands? Can the magnetic moment distinguish between the electron configurations of Mn³⁺ with a weak-field and strong-field ligand?