Which of the following complex will show largest splitting of d-orbitals ?

Options

A. `[Fe(C_(2)O_(4))_(3)]^(3-)`
B. `[Fe(CN)_(6)]^(3-)`
C. `[Fe(NH_(3))_(6)]^(3+)`
D. `[Fe(NH_(3))_(6)]^(3+),`

Answer

To determine which complex will show the largest splitting of d-orbitals, we need to consider the nature of the ligands involved in the complexes. The splitting of d-orbitals in transition metal complexes is influenced by the strength of the ligands, which can be classified as strong field ligands or weak field ligands.

### Step-by-Step Solution:

1. **Identify the Ligands**:
The ligands given in the question are oxalate, cyanide, and amine. We need to classify these ligands based on their field strength.

2. **Classify the Ligands**:
- **Oxalate (C2O4^2-)**: This is a bidentate ligand and is considered a moderate field ligand.
- **Cyanide (CN^-)**: This is a strong field ligand, known for causing significant splitting of d-orbitals.
- **Amine (NH3)**: This is also a strong field ligand, but not as strong as cyanide.

3. **Determine the Field Strength**:
Based on the ligand classification:
- Strong field ligands: Cyanide (CN^-), Amine (NH3)
- Moderate field ligands: Oxalate (C2O4^2-)

4. **Compare the Ligands**:
Since cyanide is the strongest ligand among the options provided, it will cause the largest splitting of d-orbitals compared to oxalate and amine.

5. **Conclusion**:
Therefore, the complex containing cyanide (CN^-) will show the largest splitting of d-orbitals.

### Final Answer:
The complex with cyanide (CN^-) will show the largest splitting of d-orbitals.