The octahedral complex/complex ion which shows both facial and meridional isomers is

Options

A. triglycinato cobalt (II)
B. tris (ethylene diamine) cobalt (III)
C. dichloro diglycinato cobalt (III)
D. trioxalate cobaltate (III)

Answer

To solve the question regarding the octahedral complex that shows both facial and meridional isomers, we can follow these steps:

### Step 1: Understand the Types of Isomerism
Facial (fac) and meridional (mer) isomers occur in octahedral complexes with the general formula MA3B3 or MAB3, where:
- A and B are different ligands.
- In the case of bidentate ligands, the two donor atoms must be different.

### Step 2: Analyze the Given Options
We have four options to analyze:
1. Triglycinatocobalt(II) - [Co(Gly)3]²⁻
2. Tris(ethylene diamine)cobalt(III) - [Co(en)3]³⁺
3. Dichloro-diglycinatocobalt(III) - [CoCl2(Gly)2]³⁺
4. Trioxalate cobaltate(III) - [Co(C2O4)3]³⁻

### Step 3: Examine Each Complex
1. **Triglycinatocobalt(II)**:
- Glycinato (Gly) is a bidentate ligand with two different donor atoms (N and O).
- The structure allows for both fac and mer isomers.
- **Conclusion**: This complex can show both isomers.

2. **Tris(ethylene diamine)cobalt(III)**:
- Ethylene diamine (en) is a bidentate ligand but has the same donor atoms (both N).
- **Conclusion**: This complex cannot show fac and mer isomers.

3. **Dichloro-diglycinatocobalt(III)**:
- Contains chloro (Cl) and glycinato ligands.
- The glycinato ligand has different donor atoms, but the presence of Cl does not allow for fac and mer isomers.
- **Conclusion**: This complex cannot show fac and mer isomers.

4. **Trioxalate cobaltate(III)**:
- Oxalate (C2O4) is a bidentate ligand with the same donor atoms (O).
- **Conclusion**: This complex cannot show fac and mer isomers.

### Step 4: Identify the Correct Answer
From the analysis, the only complex that can show both facial and meridional isomers is **Triglycinatocobalt(II)**.

### Final Answer
The octahedral complex that shows both facial and meridional isomers is **Triglycinatocobalt(II)**.

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