In which species the hybrid state of central atom is / are `sp^(3)d` ?

Options

A. `I_(3)^(-)`
B. `SF_(4)`
C. `PF_(5)`
D. `IF_(5)`

Answer

To determine which species have a central atom with a hybrid state of `sp^3d`, we can follow these steps:

### Step 1: Understand Hybridization and Steric Number
Hybridization is the concept of mixing atomic orbitals to form new hybrid orbitals. The hybrid state can be determined using the steric number, which is the sum of the number of bonding pairs and lone pairs around the central atom.

- **Steric Number = Number of Bond Pairs + Number of Lone Pairs**
- Hybridization types based on steric number:
- Steric number 2: `sp`
- Steric number 3: `sp^2`
- Steric number 4: `sp^3`
- Steric number 5: `sp^3d`
- Steric number 6: `sp^3d^2`

### Step 2: Analyze Each Species
1. **I3- (Triiodide Ion)**
- Iodine (I) has 7 valence electrons.
- In I3-, the central iodine atom forms 2 bonds with other iodine atoms and has 3 lone pairs.
- Steric number = 2 (bond pairs) + 3 (lone pairs) = 5.
- Therefore, the hybridization is `sp^3d`.

2. **SF4 (Sulfur Tetrafluoride)**
- Sulfur (S) has 6 valence electrons.
- In SF4, sulfur forms 4 bonds with fluorine and has 1 lone pair.
- Steric number = 4 (bond pairs) + 1 (lone pair) = 5.
- Therefore, the hybridization is `sp^3d`.

3. **PF5 (Phosphorus Pentafluoride)**
- Phosphorus (P) has 5 valence electrons.
- In PF5, phosphorus forms 5 bonds with fluorine and has no lone pairs.
- Steric number = 5 (bond pairs) + 0 (lone pairs) = 5.
- Therefore, the hybridization is `sp^3d`.

4. **IF5 (Iodine Pentafluoride)**
- Iodine (I) has 7 valence electrons.
- In IF5, iodine forms 5 bonds with fluorine and has 1 lone pair.
- Steric number = 5 (bond pairs) + 1 (lone pair) = 6.
- Therefore, the hybridization is `sp^3d^2`, not `sp^3d`.

### Step 3: Conclusion
The species with a central atom that has a hybrid state of `sp^3d` are:
- I3- (Triiodide Ion)
- SF4 (Sulfur Tetrafluoride)
- PF5 (Phosphorus Pentafluoride)

### Final Answer
The correct species are I3-, SF4, and PF5.

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