In which of the following molecules all A - X bond lengths are identical? [A = central atom and X = surrounding atom]

Options

A. `XeF_4`
B. `PF_5`
C. Both A and B
D. `SF_4`

Answer

To determine which of the given molecules has identical A-X bond lengths, we will analyze each option step by step.

### Step 1: Analyze Xenon Tetrafluoride (XeF4)
- **Structure**: XeF4 has a square planar geometry due to the presence of two lone pairs on the xenon atom.
- **Bond Lengths**: In a square planar molecule, all A-X bond lengths are equal. Therefore, all Xe-F bond lengths in XeF4 are identical.

### Step 2: Analyze Phosphorus Pentafluoride (PF5)
- **Structure**: PF5 has a trigonal bipyramidal geometry.
- **Bond Lengths**: In this structure, there are two types of bonds: axial and equatorial. The equatorial PF bonds are shorter than the axial PF bonds. Thus, the bond lengths in PF5 are not identical.

### Step 3: Analyze Sulfur Tetrafluoride (SF4)
- **Structure**: SF4 has a seesaw geometry due to one lone pair on the sulfur atom.
- **Bond Lengths**: Similar to PF5, SF4 also has two types of bond lengths: the axial SF bonds and the equatorial SF bonds. These bond lengths are different, so they are not identical.

### Conclusion
After analyzing all the options:
- **XeF4** has identical bond lengths.
- **PF5** and **SF4** do not have identical bond lengths.

Thus, the molecule in which all A-X bond lengths are identical is **Xenon Tetrafluoride (XeF4)**.

### Final Answer
**XeF4** is the correct answer.

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