How would you account for the following :
`Ni(CO)_4` possesses tetrahedral geometry while `[Pt(NH_3)_2Cl_2]` is square planar.

Explanation

To account for the different geometries of `Ni(CO)₄` and `[Pt(NH₃)₂Cl₂]`, we need to analyze the oxidation states, electronic configurations, and hybridization of the central metal ions in each complex.

### Step-by-Step Solution:

1. **Determine the Oxidation State of Nickel in Ni(CO)₄**:
- In `Ni(CO)₄`, CO is a neutral ligand (charge = 0).
- Let the oxidation state of Ni be \( x \).
- The overall charge of the complex is 0.
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