Which of the following pairs represents linkage isomers?

Options

A. `[Cu(NH_(3))_(4)] [Pt Cl_(4)] and [Pt (NH_(3))_(4)] [CuCl_(4)]`
B. `[Pb(P " "Ph_(3))_(2) (NCS)_(2)] and [Pb (P Ph_(3))_(2) (SCN)_(2)]`
C. `[Co(NH_(3))_(5) NO_(3)] SO_(4) and [CO (NH_(3))_(5) SO_(4)] NO_(3)`
D. `[Pt Cl_(2) (NH_(3))_(4] Br_(2) and [Pt Br_(2) (NH_(3))_(4)] Cl_(2)`

Answer

To determine which of the given pairs represents linkage isomers, we first need to understand the concept of linkage isomerism and ambidentate ligands.

### Step-by-Step Solution:

1. **Understanding Linkage Isomers**:
Linkage isomers are a type of isomerism that occurs in coordination compounds. They arise when a ligand can coordinate to the metal center through different atoms. This often involves ambidentate ligands, which have more than one donor atom.

2. **Identifying Ambidentate Ligands**:
An ambidentate ligand can bind to a metal ion through two different atoms. A common example is the thiocyanate ion (SCN⁻), which can bind through either the sulfur (S) or the nitrogen (N) atom.

3. **Analyzing the Options**:
We need to look at the pairs provided in the options to see if any contain ambidentate ligands.

4. **Example of SCN⁻**:
For instance, if we have a pair that includes [M(SCN)₂] where one is bound through sulfur and the other through nitrogen, this would represent linkage isomers.

5. **Evaluating Each Option**:
- **Option 1**: Contains ligands that do not exhibit ambidentate behavior.
- **Option 2**: Contains SCN⁻ as a ligand, which can bind through either sulfur or nitrogen, thus representing linkage isomers.
- **Option 3**: Similar to option 1, does not show linkage isomerism.
- **Option 4**: Again does not contain ambidentate ligands.

6. **Conclusion**:
The only pair that represents linkage isomers is the one that includes SCN⁻, as it can coordinate through different atoms.

### Final Answer:
The correct option that represents linkage isomers is **Option 2**, which includes the ambidentate ligand SCN⁻.

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