Which is iso-structural ?

Options

A. `XeF_(2),Icl_(2)^(-),ClF_(3)`
B. `ClF_(3),PCl_(3),NCl_(3)`
C. `CO_(2),XeF_(2),I_(3)^(-)`
D. `PCl_(5),XeOF_(2),ICl_(5)`

Answer

To determine which of the given compounds are iso-structural, we need to analyze the molecular geometry of each compound in the options provided. Iso-structural compounds have the same or similar molecular shapes.

### Step-by-Step Solution:

1. **Understanding Iso-structural Compounds:**
- Iso-structural compounds have similar shapes and structures. We will analyze the geometry of the given compounds in each option.

2. **Analyzing the First Option:**
- **Compounds:** XeF2 and ICl2^-
- **XeF2:** This compound has a linear structure with the central xenon atom bonded to two fluorine atoms and three lone pairs.
- **ICl2^-:** This compound also has a linear structure with iodine in the center bonded to two chlorine atoms and three lone pairs.
- **Conclusion for First Option:** Both XeF2 and ICl2^- are linear, thus they are iso-structural.

3. **Analyzing the Second Option:**
- **Compounds:** ClF3, PCl3, NCl3
- **ClF3:** This compound has a T-shaped structure due to the presence of two lone pairs on the central chlorine atom.
- **PCl3:** This compound has a trigonal pyramidal structure with one lone pair on the phosphorus atom.
- **NCl3:** Similar to PCl3, it also has a trigonal pyramidal structure with one lone pair on the nitrogen atom.
- **Conclusion for Second Option:** ClF3 is not iso-structural with PCl3 and NCl3 as they have different shapes.

4. **Analyzing the Third Option:**
- **Compounds:** CO2, XeF2, I3^-
- **CO2:** This compound has a linear structure with two double bonds between carbon and two oxygen atoms.
- **XeF2:** As analyzed before, it has a linear structure.
- **I3^-:** This ion also has a linear structure with three iodine atoms, where the central iodine is bonded to two terminal iodine atoms and has three lone pairs.
- **Conclusion for Third Option:** All three compounds (CO2, XeF2, and I3^-) are linear, thus they are iso-structural.

5. **Analyzing the Fourth Option:**
- **Compounds:** PCl5, XeOF2, ICl5
- **PCl5:** This compound has a trigonal bipyramidal structure.
- **XeOF2:** This compound has a seesaw structure due to the presence of two lone pairs.
- **ICl5:** This compound has a square pyramidal structure.
- **Conclusion for Fourth Option:** None of these compounds are iso-structural as they have different geometries.

### Final Answer:
The correct option that contains iso-structural compounds is **Option 3** (CO2, XeF2, I3^-).