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 of the given species uses both axial sets of d-orbitals in the hybridization of the central atom, we need to analyze the hybridization of each species listed in the options. The axial d-orbitals are specifically the \(d_{z^2}\) and \(d_{x^2-y^2}\) orbitals.

### Step-by-Step Solution:

1. **Identify the Axial d-Orbitals**:
- The axial d-orbitals are \(d_{z^2}\) and \(d_{x^2-y^2}\). These orbitals are oriented along the vertical and horizontal axes, respectively.

2. **Analyze Each Option**:
- **Option A: \(PBr_4^+\)**:
- The structure is tetrahedral, and the hybridization is \(sp^3\).
- Since it does not involve any d-orbitals, this option does not satisfy the requirement.

- **Option B: \(PCl_4^-\)**:
- The structure is a seesaw shape with a lone pair on the central phosphorus atom.
- The hybridization is \(sp^3d\), which means only one d-orbital is used (the \(d_{z^2}\) or \(d_{x^2-y^2}\)), so this option also does not satisfy the requirement.

- **Option C: \(ICl_4^-\)**:
- The structure is square planar, with four chlorine atoms in the same plane and two lone pairs positioned above and below the plane.
- The hybridization here is \(sp^3d^2\), which means both axial d-orbitals (\(d_{z^2}\) and \(d_{x^2-y^2}\)) are utilized in the hybridization of iodine.
- Therefore, this option satisfies the requirement.

3. **Conclusion**:
- The species that uses both axial sets of d-orbitals in hybridization of the central atom is **Option C: \(ICl_4^-\)**.

### Final Answer:
**The correct answer is Option C: \(ICl_4^-\)**.