Which of the following does not exist?

Options

A. `XeOF_4`
B. `NeF_2`
C. `XeF_2`
D. `XeF_6`

Explanation

To determine which of the following compounds does not exist, we need to analyze the given options: XZOF4, NEF2, XZF2, and XZF6.

### Step-by-Step Solution:

1. **Identify the Elements**:
- XZOF4: Here, X is likely xenon (Xe) and O is oxygen (O).
- NEF2: Here, N is neon (Ne) and F is fluorine (F).
- XZF2: Here, X is xenon (Xe) and F is fluorine (F).
- XZF6: Here, X is xenon (Xe) and F is fluorine (F).

2. **Understanding Noble Gases**:
- Noble gases like xenon and neon are known for their lack of reactivity due to their complete valence electron shells. However, xenon can form compounds due to the presence of empty d-orbitals in its electron configuration.

3. **Analyzing Each Compound**:
- **XZOF4**: Xenon can form compounds with oxygen and fluorine, so this compound can exist.
- **NEF2**: Neon does not have the ability to form stable compounds due to its full valence shell and lack of available d-orbitals. Therefore, this compound does not exist.
- **XZF2**: Xenon can form compounds with fluorine, so this compound can exist.
- **XZF6**: Similarly, xenon can also form this compound with fluorine, so it can exist.

4. **Conclusion**:
- Among the given options, **NEF2** does not exist because neon cannot form stable compounds due to its electronic configuration and lack of available d-orbitals.

### Final Answer:
**NEF2 does not exist.**