Which of the following halides has `Cl^(-)` as a bridging atom?

Options

A. `BeCl_(2)`(solid)
B. `Al_(2)Cl_(6)`(liquid)
C. `Fe_(2)Cl_(6)`
D. All of these

Answer

To determine which of the given halides has `Cl^(-)` as a bridging atom, we will analyze the structures of the halides mentioned in the question.

### Step-by-Step Solution:

1. **Understanding the Concept of Bridging Atoms**:
- A bridging atom is an atom that connects two or more atoms in a molecule. In the context of halides, we are looking for halides where the chloride ion (`Cl^(-)`) acts as a bridge between two metal atoms.

2. **Analyzing BeCl2**:
- Beryllium chloride (BeCl2) in its solid state has a polymeric chain structure.
- Beryllium is tetrahedrally surrounded by chlorine atoms.
- In this structure, some chlorine atoms donate their lone pairs to beryllium, forming coordinate bonds.
- As a result, there are bridging chlorine atoms between two beryllium atoms.
- **Conclusion**: BeCl2 has `Cl^(-)` as a bridging atom.

3. **Analyzing Al2Cl6**:
- Aluminium chloride (Al2Cl6) exists in a liquid state and has a dimeric structure.
- Each aluminium atom is surrounded by chlorine atoms, and due to the electron deficiency of aluminium, it accepts lone pairs from chlorine.
- In this structure, some chlorine atoms bridge between two aluminium atoms.
- **Conclusion**: Al2Cl6 has `Cl^(-)` as a bridging atom.

4. **Analyzing Fe2Cl6**:
- Iron(III) chloride (Fe2Cl6) also has a structure where chlorine atoms bridge between two iron atoms.
- Similar to the previous cases, the bridging occurs due to the coordination of chlorine with the iron atoms.
- **Conclusion**: Fe2Cl6 has `Cl^(-)` as a bridging atom.

5. **Final Conclusion**:
- All three compounds (BeCl2, Al2Cl6, and Fe2Cl6) have `Cl^(-)` as bridging atoms.
- Therefore, the correct answer is that all of the given halides have `Cl^(-)` as a bridging atom.

### Final Answer:
All of the above halides (BeCl2, Al2Cl6, and Fe2Cl6) have `Cl^(-)` as a bridging atom.

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