Which of the following complexes form facial and meridional isomers?

Options

A. `[Cr(H_(2)O)_(5)CI]^(+2)`
B. `[Cr(NH_(2))_(5)Br]SO_(4)`
C. `[Cr(NH_(3))_(3)(NO_(2))_(3)]`
D. `[Cr(ox_(3)]^(3-)`

Answer

To determine which of the given complexes can form facial and meridional isomers, we need to analyze the coordination geometry and the types of ligands involved in each complex. Facial and meridional isomers are specific to octahedral complexes with the formula MA3B3, where M is the metal center, A is one type of ligand, and B is another type of ligand.

### Step-by-Step Solution:

1. **Identify the Coordination Number and Geometry**:
- All complexes mentioned are octahedral, which means they have a coordination number of 6.

2. **Analyze Each Complex**:
- **Option 1: CrH2O5Cl**
- This complex has 5 water ligands and 1 chloride ligand. It does not fit the MA3B3 type because it has 5 of one kind of ligand and only 1 of another.
- **Conclusion**: Cannot form facial and meridional isomers.

- **Option 2: CrNH3O5BrSO4**
- This complex has 5 of one type of ligand (NH3) and 2 of another (Br and SO4). It does not fit the MA3B3 type either.
- **Conclusion**: Cannot form facial and meridional isomers.

- **Option 3: CrNH3O3NO2O3**
- This complex has 3 NH3 ligands and 3 NO2 ligands. It fits the MA3B3 type.
- **Facial Isomer**: In the facial isomer, the three NH3 ligands occupy one face of the octahedron.
- **Meridional Isomer**: In the meridional isomer, one of the NH3 ligands occupies an equatorial position, along with the NO2 ligands.
- **Conclusion**: Can form facial and meridional isomers.

- **Option 4: CrOXO3-**
- This complex has 3 oxo ligands and does not fit the MA3B3 type.
- **Conclusion**: Cannot form facial and meridional isomers.

3. **Final Conclusion**:
- The only complex that can form facial and meridional isomers is **Option 3: CrNH3O3NO2O3**.

### Answer:
**The correct answer is Option 3: CrNH3O3NO2O3.**