Which of the following does not contain `PX_(4)^(+)` type cation in
crystalline phase?(`X=halogen`)

Options

A. `PF_(5)`
B. `PCl_(5)`
C. `PBr_(5)`
D. None of these

Explanation

To solve the question of which compound does not contain the `PX₄⁺` type cation in the crystalline phase, we need to analyze the phosphorus pentahalides given in the options. The compounds to consider are PF₅, PCl₅, and PBr₅.

### Step-by-Step Solution:

1. **Understanding the Compounds**:
- We are dealing with phosphorus pentahalides, which can be represented as `PX₅`, where `X` is a halogen (F, Cl, Br).
- The question specifically asks about the presence of `PX₄⁺` type cations in the crystalline phase.

2. **Analyzing PF₅**:
- PF₅ (phosphorus pentafluoride) has fluorine as the halogen.
- In the crystalline phase, PF₅ exists as a stable molecular solid due to the small size of fluorine atoms.
- It does not form `PF₄⁺` cations because the small size of F leads to a stable molecular arrangement without the need for ionic forms.

3. **Analyzing PCl₅**:
- PCl₅ (phosphorus pentachloride) has chlorine as the halogen.
- In the crystalline phase, PCl₅ can exist as `PCl₄⁺` and `PCl₆⁻` due to the larger size of chlorine compared to fluorine, which allows for ionic interactions.
- Thus, PCl₅ does contain `PCl₄⁺` type cations.

4. **Analyzing PBr₅**:
- PBr₅ (phosphorus pentabromide) has bromine as the halogen.
- Similar to PCl₅, PBr₅ can also exist as `PBr₄⁺` and `PBr₆⁻` in the crystalline phase due to the larger size of bromine, allowing for ionic forms.
- Therefore, PBr₅ also contains `PBr₄⁺` type cations.

5. **Conclusion**:
- Among PF₅, PCl₅, and PBr₅, only PF₅ does not contain `PX₄⁺` type cations in the crystalline phase.
- The answer is **PF₅**.