Question

Calculate the oxidation state and coordination number of central metal atom in the K₃ [Fe(C₂O₄)₃]

Answer 1

As K⁺ ion carries charge = +1, charge on 3K ions = +3.
Hence charge on complex ion = +3. As each oxalate ion C₂O^2-₄ has charge = +2, charge on three C₂O^2-₄ = -6. Therefore charge on Fe should be = +3 i.e., oxidation number of Fe in the given complex = +3. Coordination number of ligand = No. of ligand x Denticity
= 3 x 2 = 6 .