The geometry of `Ni(CO_(4))` and `Ni(PPh_(3))_(2)Cl_(2)` are

Options

A. both square planar
B. tetrahedral and square planar
C. both tetrahedral
D. square planar and tetrahedral .

Explanation

To determine the geometry of the coordination compounds `Ni(CO)_(4)` and `Ni(PPh_(3))_(2)Cl_(2)`, we can follow these steps:

### Step 1: Analyze `Ni(CO)_(4)`

1. **Determine the oxidation state of Ni**: In `Ni(CO)_(4)`, carbon monoxide (CO) is a neutral ligand. Therefore, the oxidation state of nickel (Ni) is 0.

2. **Find the electronic configuration of Ni**: The electronic configuration of Ni in its elemental state is `[Ar] 4s² 3d⁸`.

3. **Consider the effect of CO as a ligand**: CO is a strong field ligand, which means it will cause pairing of electrons. In this case, the two 4s electrons will pair with two of the 3d electrons, resulting in a configuration of `3d¹⁰`.

4. **Determine the hybridization**: Since there are four CO ligands, the hybridization will be `sp³`.

5. **Identify the geometry**: The `sp³` hybridization corresponds to a tetrahedral geometry.

### Step 2: Analyze `Ni(PPh_(3))_(2)Cl_(2)`

1. **Determine the oxidation state of Ni**: In `Ni(PPh_(3))_(2)Cl_(2)`, the phosphine (PPh₃) is a neutral ligand, and chloride (Cl) has a -1 charge. Therefore, the oxidation state of nickel is +2.

2. **Find the electronic configuration of Ni**: For Ni in the +2 oxidation state, the electronic configuration is `4s² 3d⁸`. When Ni loses two electrons, they are removed from the 4s orbital, resulting in `3d⁸`.

3. **Consider the effect of PPh₃ and Cl as ligands**: Both PPh₃ and Cl are weak field ligands, meaning they do not cause significant pairing of electrons. The 3d electrons remain unpaired.

4. **Determine the hybridization**: There are two PPh₃ ligands and two Cl ligands, leading to a total of four ligands. The hybridization will also be `sp³`.

5. **Identify the geometry**: The `sp³` hybridization corresponds to a tetrahedral geometry.

### Final Conclusion

Both `Ni(CO)_(4)` and `Ni(PPh_(3))_(2)Cl_(2)` exhibit tetrahedral geometry.