Which of the following inter-halogen compounds does not exist ? 

Options

A. `IF_7`
B. `ClF_3`
C. `Icl`
D. `BrCl_7`

Answer

To determine which of the following inter-halogen compounds does not exist, we will analyze each option based on the size of the halogen atoms and their ability to form stable compounds. The options provided are IF7, ClF3, ICl, and BrCl7.

### Step-by-Step Solution:

1. **Analyze IF7:**
- Iodine (I) is a large atom and can accommodate seven fluorine (F) atoms around it due to its size.
- The compound IF7 is stable and does exist.

2. **Analyze ClF3:**
- Chlorine (Cl) can bond with three fluorine (F) atoms.
- The size of fluorine is smaller compared to chlorine, allowing the formation of ClF3.
- This compound is also stable and does exist.

3. **Analyze ICl:**
- Iodine (I) can bond with chlorine (Cl) to form ICl.
- Both atoms can accommodate each other due to their sizes, and ICl is a known stable compound.

4. **Analyze BrCl7:**
- Bromine (Br) is not large enough to accommodate seven chlorine (Cl) atoms around it.
- The size of bromine is smaller than iodine, and thus it cannot stabilize seven chlorine atoms due to steric repulsions.
- Therefore, BrCl7 does not exist as a stable compound.

### Conclusion:
The inter-halogen compound that does not exist is **BrCl7**.

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