Which of the following complexes show linkage isomerism ?

Options

A. `[Co(NH_(3))_(5)(NO_(2))]^(2+)`
B. `[Co(H_(2)O)_(5)CO]^(3+)`
C. `[Cr(NH_(3))_(5)]SCN^(2+)`
D. `[Fe(en)_(2)Cl_(2)]^(+)`

Explanation

To determine which of the given complexes show linkage isomerism, we need to identify the presence of ambidentate ligands in each complex. Ambidentate ligands are those that have two different donor atoms that can bind to the metal center.

### Step-by-Step Solution:

1. **Identify the Ligands in Each Complex**:
- For each complex, list the ligands present.

2. **Determine if the Ligands are Ambidentate**:
- Check if any of the ligands in the complexes are ambidentate. Ambidentate ligands have two different donor atoms that can coordinate with the metal ion.

3. **Analyze Each Complex**:
- **Complex 1**: Contains NH3 (ammonia) and NO2 (nitrite).
- NH3 is a monodentate ligand (one donor site).
- NO2 is an ambidentate ligand (can bind through nitrogen or oxygen).
- Conclusion: This complex can show linkage isomerism.

- **Complex 2**: Contains H2O (water) and CO (carbon monoxide).
- Both H2O and CO are monodentate ligands.
- Conclusion: This complex cannot show linkage isomerism.

- **Complex 3**: Contains NH3 (ammonia) and SCN (thiocyanate).
- NH3 is a monodentate ligand.
- SCN is an ambidentate ligand (can bind through sulfur or nitrogen).
- Conclusion: This complex can show linkage isomerism.

- **Complex 4**: Contains ethylenediamine (en) and Cl- (chloride).
- Ethylenediamine is a bidentate ligand (two donor sites but both are nitrogen).
- Cl- is a monodentate ligand.
- Conclusion: This complex cannot show linkage isomerism.

4. **Final Conclusion**:
- The complexes that can show linkage isomerism are Complex 1 (NO2) and Complex 3 (SCN).

### Answer:
The complexes that show linkage isomerism are **Complex 1** and **Complex 3**.

---