Which theory can explain bonding ` Ni ( CO ) _ 4 `

Options

A. MOT
B. CFT
C. VBT
D. Werner's theory

Answer

To determine which theory can explain the bonding in nickel tetracarbonyl (Ni(CO)₄), we can analyze the characteristics of the compound and the theories available.

### Step-by-Step Solution:

1. **Identify the Compound**:
- The compound in question is nickel tetracarbonyl, Ni(CO)₄. It consists of a nickel (Ni) atom bonded to four carbon monoxide (CO) ligands.

2. **Consider the Theories**:
- The theories we need to evaluate are:
- Molecular Orbital Theory (MOT)
- Valence Bond Theory (VBT)
- Crystal Field Theory (CFT)
- Werner's Theory

3. **Analyze the Nature of CO Ligands**:
- Carbon monoxide (CO) is a strong field ligand and is known to promote the pairing of electrons. This characteristic is crucial in determining the hybridization and geometry of the complex.

4. **Hybridization and Geometry**:
- In Ni(CO)₄, the nickel atom undergoes sp³ hybridization due to the presence of four CO ligands. This results in a tetrahedral geometry for the complex.

5. **Magnetic Properties**:
- Ni(CO)₄ is diamagnetic, meaning it has no unpaired electrons. This is consistent with the idea that all electrons are paired due to the strong field nature of the CO ligands.

6. **Bonding Mechanism**:
- The bonding in Ni(CO)₄ involves sigma bonding and back-bonding. The CO ligands donate electron density to the nickel atom, forming sigma bonds. Additionally, there is back-bonding where the filled d-orbitals of nickel interact with the empty π* orbitals of CO, stabilizing the complex.

7. **Conclusion**:
- Given the above analysis, Molecular Orbital Theory (MOT) provides the best explanation for the bonding in Ni(CO)₄. It accounts for the hybridization, geometry, and the nature of the bonding interactions (including back-bonding).

### Final Answer:
The theory that can explain bonding in nickel tetracarbonyl (Ni(CO)₄) is **Molecular Orbital Theory (MOT)**.