Three types of FXF angles are present in which of the following molecule (X=S,Xe,C).

Options

A. `SF_4`
B. `XeF_4`
C. `SF_6`
D. `CF_4`.

Answer

To solve the question about which molecule has three types of FXF angles, we will analyze the three given molecules: SF4, XeF4, and CF4.

### Step-by-Step Solution:

1. **Identify the Molecules and Their Composition**:
- SF4 (Sulfur Tetrafluoride)
- XeF4 (Xenon Tetrafluoride)
- CF4 (Carbon Tetrafluoride)

2. **Determine the Valence Electrons**:
- **SF4**: Sulfur (S) has 6 valence electrons, and each Fluorine (F) has 1 valence electron. Therefore, total valence electrons = 6 + (4 × 1) = 10.
- **XeF4**: Xenon (Xe) has 8 valence electrons, and each Fluorine (F) has 1 valence electron. Therefore, total valence electrons = 8 + (4 × 1) = 12.
- **CF4**: Carbon (C) has 4 valence electrons, and each Fluorine (F) has 1 valence electron. Therefore, total valence electrons = 4 + (4 × 1) = 8.

3. **Determine the Bond Pairs and Lone Pairs**:
- **SF4**: Sulfur forms 4 bonds with Fluorine and has 1 lone pair.
- **XeF4**: Xenon forms 4 bonds with Fluorine and has 2 lone pairs.
- **CF4**: Carbon forms 4 bonds with Fluorine and has 0 lone pairs.

4. **Calculate the Steric Number and Hybridization**:
- **SF4**: Steric number = 5 (4 bond pairs + 1 lone pair), Hybridization = sp³d.
- **XeF4**: Steric number = 6 (4 bond pairs + 2 lone pairs), Hybridization = sp³d².
- **CF4**: Steric number = 4 (4 bond pairs + 0 lone pairs), Hybridization = sp³.

5. **Determine the Geometry and Bond Angles**:
- **SF4**: Geometry is trigonal bipyramidal. The angles are approximately:
- Axial-Axial: 180°
- Equatorial-Equatorial: 120°
- Axial-Equatorial: approximately 90°.
- Thus, SF4 has three distinct bond angles.
- **XeF4**: Geometry is octahedral. The angles are:
- All bond angles are 90° and 180°. Thus, it does not have three distinct angles.
- **CF4**: Geometry is tetrahedral. The bond angle is 109.5°. Thus, it does not have three distinct angles.

6. **Conclusion**:
- The molecule that has three types of FXF angles is **SF4**.

### Final Answer:
**SF4** has three types of FXF angles.