Which of the following species used both axial set of d-orbitals in hybridisation of central atom ?

Options

A. `PBr_(4)^(+)`
B. `PCl_(4)^(-)`
C. `IC l_(4)^(-)`
D. none of these

Answer

To determine which species uses both axial sets of d-orbitals in the hybridization of the central atom, we need to analyze the hybridization states of the given species. The axial set of d-orbitals refers to the d_z^2 and d_x^2 - y^2 orbitals, which are involved in sp^3d^2 hybridization.

### Step-by-Step Solution:

1. **Identify the Hybridization Type**:
- The axial set of d-orbitals indicates that we are looking for a hybridization of sp^3d^2, which involves two d-orbitals.

2. **Calculate the Steric Number**:
- The steric number is calculated as the sum of the number of sigma bonds and lone pairs around the central atom.
- The formula is:
\[ \text{Steric Number} = \text{Number of Sigma Bonds} + \text{Number of Lone Pairs} \]

3. **Analyze Each Species**:
- **PBr4+**:
- It has 4 sigma bonds and no lone pairs.
- Steric Number = 4 + 0 = 4.
- Hybridization = sp^3 (not sp^3d^2).

- **PCl4-**:
- It has 4 sigma bonds and 1 lone pair.
- Steric Number = 4 + 1 = 5.
- Hybridization = sp^3d (not sp^3d^2).

- **SCl4-**:
- It has 4 sigma bonds and 2 lone pairs.
- Steric Number = 4 + 2 = 6.
- Hybridization = sp^3d^2 (this uses both axial sets of d-orbitals).

4. **Conclusion**:
- The species that uses both axial sets of d-orbitals in hybridization is **SCl4-** (or ICl4- depending on the context provided in the question).

### Final Answer:
The correct answer is **SCl4-** (or ICl4- if applicable).