Question

What is the coordination number of central metal ion in [Fe(C₂O₄)₃]³⁻?

Answer 1

Complex ion: [Fe(C₂O₄)₃]³⁻

Central metal: Fe

Ligand: C₂O₄²⁻

Oxalate is a bidentate ligand (attaches at 2 points)

Number of oxalate ligands = 3

Coordination number = 3 × 2 

= 6