Which of the following is a hypervalent compound?

Options

A. `BF_3`
B. `Al_2Cl_3`
C. `SF_6`
D. `PCl_3`

Answer

To determine which of the given compounds is a hypervalent compound, we need to analyze the valence electrons of each compound. A hypervalent compound is defined as one that has more than 8 valence electrons around the central atom.

### Step-by-Step Solution:

1. **Understand Hypervalency**:
- Hypervalent compounds have more than 8 electrons in their valence shell. This typically occurs in elements from the third period and beyond, which can utilize d-orbitals for bonding.

2. **Analyze BF3**:
- Boron (B) has 3 valence electrons, and each fluorine (F) contributes 1 valence electron.
- Total valence electrons = 3 (from B) + 3 × 1 (from 3 F) = 6 electrons.
- Since 6 < 8, BF3 is not hypervalent.

3. **Analyze Al2Cl3**:
- Aluminum (Al) has 3 valence electrons, and chlorine (Cl) has 7 valence electrons.
- If we consider AlCl3, total valence electrons = 3 (from Al) + 3 × 7 (from 3 Cl) = 24 electrons.
- However, AlCl3 is typically considered hypovalent as Al can only accommodate 6 electrons in its valence shell.
- Therefore, Al2Cl3 is not hypervalent.

4. **Analyze SF6**:
- Sulfur (S) has 6 valence electrons, and each fluorine (F) contributes 1 valence electron.
- Total valence electrons = 6 (from S) + 6 × 1 (from 6 F) = 12 electrons.
- Since 12 > 8, SF6 is hypervalent.

5. **Conclusion**:
- Among the given options, SF6 is the only hypervalent compound.

### Final Answer:
The hypervalent compound is **SF6**.

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