Which of the following compound donot exist?

Options

A. `PCl_(5)`
B. `OF_(6)`
C. `OF_(2)`
D. `BrF_(5)`

Answer

To determine which of the following compounds does not exist, we need to analyze the electronic configuration and bonding capabilities of the elements involved in the compounds.

### Step-by-Step Solution:

1. **Identify the Compounds**: We need to look at the list of compounds provided in the question. For this solution, we will focus on the compound OF6 (Oxygen Difluoride).

2. **Understand the Electronic Configuration of Oxygen**: The electronic configuration of oxygen (O) is 1s² 2s² 2p⁴. This means that oxygen has a total of 8 electrons, filling its 1s and 2s orbitals and partially filling its 2p orbitals.

3. **Determine the Valence Shell and Covalency**: The valence shell of oxygen can accommodate a maximum of 8 electrons. Since oxygen has 6 valence electrons (2s² 2p⁴), it can form a maximum of 4 covalent bonds (as it needs to gain 2 more electrons to complete its octet).

4. **Analyze the Compound OF6**: In the compound OF6, oxygen would need to form 6 bonds with fluorine atoms. This would require oxygen to accommodate 12 electrons (6 pairs), which exceeds its maximum capacity of 8 electrons.

5. **Check for Vacant D Orbitals**: Oxygen does not have vacant d orbitals that could allow it to expand its octet. The absence of d orbitals in the second period of the periodic table means that oxygen cannot form more than 4 covalent bonds.

6. **Conclusion**: Since oxygen cannot accommodate more than 8 electrons and cannot form 6 bonds, the compound OF6 cannot exist. Therefore, the answer to the question is that OF6 does not exist.

### Final Answer:
The compound that does not exist is **OF6**.