Which of the following pairs are iso-structural ?

Options

A. `XeF_(2),lF_(2)^(-)`
B. `NH_(3),BF_(3)`
C. `CO_(3)^(2-),SO_(3)^(2-)`
D. `PCl_(5),lCl_(5)`

Explanation

To determine which pairs are iso-structural, we need to analyze the molecular geometry and hybridization of the given compounds. Iso-structural compounds have the same shape and hybridization.

### Step-by-Step Solution:

1. **Identify the Compounds:**
We need to analyze the pairs of compounds provided in the question.

2. **Determine Molecular Geometry and Hybridization:**
- For **XeF2**:
- **Shape**: Linear
- **Hybridization**: sp³d (due to 3 lone pairs and 2 bonding pairs)
- For **IF2⁻**:
- **Shape**: Linear
- **Hybridization**: sp³d (due to 3 lone pairs and 2 bonding pairs)

Since both XeF2 and IF2⁻ have the same shape (linear) and the same hybridization (sp³d), they are iso-structural.

3. **Analyze Other Pairs:**
- For **NH3**:
- **Shape**: Trigonal pyramidal
- **Hybridization**: sp³
- For **BF3**:
- **Shape**: Trigonal planar
- **Hybridization**: sp²

Since NH3 and BF3 have different shapes and hybridizations, they are not iso-structural.

- For **Carbonate (CO3²⁻)** and **Sulfate (SO4²⁻)**:
- **Shape**: Trigonal planar for both
- **Hybridization**: sp² for both

Although they have the same shape and hybridization, they are not iso-structural because they involve different central atoms (C and S).

- For **PCl5**:
- **Shape**: Trigonal bipyramidal
- **Hybridization**: sp³d
- For **PCl6⁻**:
- **Shape**: Octahedral
- **Hybridization**: sp³d²

Since PCl5 and PCl6⁻ have different shapes and hybridizations, they are not iso-structural.

4. **Conclusion:**
The only pair that is iso-structural is **XeF2 and IF2⁻**.

### Final Answer:
The correct answer is option A: **XeF2 and IF2⁻**.