Which molecule pair do not have identical structure

Options

A. `I_(3)^(-)BeF_(2)`
B. `HClO, SO_(2)`
C. `BF_(3), lCl_(3)`
D. `Br F_(4)^(-), XeF_(4)`

Explanation

To determine which molecule pair does not have an identical structure, we will analyze the hybridization and molecular geometry of each pair of molecules provided in the options.

### Step-by-Step Solution:

1. **Analyze the first pair: I3- and BeF2**
- For **I3-**:
- Valence electrons of Iodine = 7 (for each I)
- Total = 7 * 3 = 21
- Charge = -1 (anionic charge)
- Steric number = (21 + 0 - 0 + 1) / 2 = 11 / 2 = 5
- Hybridization = sp3d
- Structure = Linear
- For **BeF2**:
- Valence electrons of Beryllium = 2
- Total = 2 + 2 * 7 (for each F) = 16
- Charge = 0
- Steric number = (16 + 0 - 0) / 2 = 8 / 2 = 4
- Hybridization = sp
- Structure = Linear
- **Conclusion**: Both have linear structures, so this option is incorrect.

2. **Analyze the second pair: HClO and SO2**
- For **HClO**:
- Valence electrons of Chlorine = 7 + 1 (for H) + 2 (for O) = 10
- Charge = 0
- Steric number = (10 + 0 - 0) / 2 = 5
- Hybridization = sp3
- Structure = Bent
- For **SO2**:
- Valence electrons of Sulfur = 6 + 0 + 2 (for O) = 8
- Charge = 0
- Steric number = (8 + 0 - 0) / 2 = 4
- Hybridization = sp2
- Structure = Bent
- **Conclusion**: Both have bent structures, so this option is incorrect.

3. **Analyze the third pair: BF3 and ICl3**
- For **BF3**:
- Valence electrons of Boron = 3 + 3 * 7 (for each F) = 24
- Charge = 0
- Steric number = (24 + 0 - 0) / 2 = 12
- Hybridization = sp2
- Structure = Trigonal planar
- For **ICl3**:
- Valence electrons of Iodine = 7 + 3 * 7 (for each Cl) = 28
- Charge = 0
- Steric number = (28 + 0 - 0) / 2 = 14
- Hybridization = sp3d
- Structure = T-shaped
- **Conclusion**: These structures are different, so this option is correct.

4. **Analyze the fourth pair: BrF4- and XeF4**
- For **BrF4-**:
- Valence electrons of Bromine = 7 + 4 * 7 (for each F) + 1 (for charge) = 30
- Charge = -1
- Steric number = (30 + 0 - 0 + 1) / 2 = 15.5
- Hybridization = sp3d2
- Structure = Square planar
- For **XeF4**:
- Valence electrons of Xenon = 8 + 4 * 7 (for each F) = 36
- Charge = 0
- Steric number = (36 + 0 - 0) / 2 = 18
- Hybridization = sp3d2
- Structure = Square planar
- **Conclusion**: Both have square planar structures, so this option is incorrect.

### Final Answer:
The molecule pair that does not have identical structure is **BF3 and ICl3**.