What is the oxidation state of iron?
K3[Fe(C2O4)3]
Group of answer choices
Fe2+
Fe3+
Fe
Fe4+
The correct answer and explanation is :
The correct answer is Fe³⁺.
To determine the oxidation state of iron in K₃[Fe(C₂O₄)₃], we can break it down step by step:
- Identify the components of the compound:
- The compound consists of a complex ion [Fe(C₂O₄)₃]³⁻ and three potassium ions (K⁺), which balance the charge of the complex.
- The C₂O₄²⁻ is the oxalate ion, which is a bidentate ligand, meaning it binds to the metal at two points. The charge of the oxalate ion is -2.
- Determine the charge on the complex ion:
- The overall charge of the complex ion [Fe(C₂O₄)₃] is ³⁻ (because the compound is neutral and there are three K⁺ ions balancing the negative charge).
- Balance the charges:
- The complex ion consists of three C₂O₄²⁻ ions. Since each oxalate ion has a charge of -2, the total negative charge contributed by the three oxalate ions is:
[
3 \times (-2) = -6
] - To balance this, the iron ion must have a positive charge of +3 (because the total charge on the complex ion is ³⁻). Therefore, the oxidation state of iron in this complex is Fe³⁺.
- Conclusion:
The oxidation state of iron in K₃[Fe(C₂O₄)₃] is Fe³⁺.
Explanation of the Answer:
In coordination chemistry, the oxidation state of the metal is determined by considering the charges of the ligands and the overall charge of the complex ion. Here, since the oxalate ion (C₂O₄²⁻) is a negatively charged ligand, and the overall charge of the complex is ³⁻, the iron atom must have a charge of +3 to balance the charges. Hence, the oxidation state of iron in this complex is Fe³⁺.
Thus, the correct answer is Fe³⁺.