Which of the following shell from an octahedral complex

Options

A. `d^(4)` (low spin)
B. `d^(8)` (high spin)
C. `d^(6)` (low spin)
D. None of these .

Explanation

To determine which of the given electron configurations can form an octahedral complex, we need to analyze each option based on the principles of coordination chemistry and crystal field theory.

### Step-by-Step Solution:

1. **Understanding Octahedral Complexes**:
- Octahedral complexes are formed when a central metal ion is surrounded by six ligands at the corners of an octahedron.
- The d-orbitals split into two sets in an octahedral field: the lower-energy t2g orbitals and the higher-energy eg orbitals.

2. **Identifying the Electron Configurations**:
- The options given are:
- d4 low spin
- d8 high spin
- d6 low spin
- none of these

3. **Analyzing Each Configuration**:
- **d4 Low Spin**:
- In a low-spin state, the electrons will fill the lower energy t2g orbitals first. For d4 low spin, the configuration would be t2g^4 eg^0. This is possible in an octahedral field with strong field ligands.
- **d8 High Spin**:
- In a high-spin state, the electrons will occupy the eg orbitals as well. For d8 high spin, the configuration would be t2g^6 eg^2. This is also possible in an octahedral field but typically occurs with weak field ligands.
- **d6 Low Spin**:
- For d6 low spin, the configuration would be t2g^6 eg^0. This is a common configuration for octahedral complexes, especially with strong field ligands.
- **None of These**:
- This option implies that none of the above configurations can form an octahedral complex, which is incorrect based on the analysis.

4. **Conclusion**:
- Among the options, d6 low spin is the most stable and common configuration that can form an octahedral complex. Therefore, the correct answer is **d6 low spin**.

### Final Answer:
The shell that forms an octahedral complex is **d6 low spin**.