Which of the following compound or ion is planar?

Options

A. `SF_(5)^(-)`
B. `SF_(4)`
C. `SOF_(4)`
D. `SF_(2)`

Explanation

To determine which of the given compounds or ions is planar, we will analyze each option based on their hybridization and molecular geometry.

### Step-by-Step Solution:

1. **Identify the Compounds/Ions**:
We are given three compounds/ions to analyze: SF5^-, SF4, and SOF4.

2. **Analyze SF5^-**:
- **Valence Electrons Calculation**:
- Sulfur (S) has 6 valence electrons.
- Each Fluorine (F) has 7 valence electrons, and there are 5 Fluorine atoms.
- Total = 6 + (7 × 5) + 1 (due to the negative charge) = 6 + 35 + 1 = 42 electrons.
- **Electron Pairs Calculation**:
- Divide 42 by 2 to find the number of electron pairs: 42 / 2 = 21 pairs.
- **Hybridization**:
- The number of bonding pairs (5) + lone pairs (1) = 6 pairs indicates sp^3d^2 hybridization.
- **Geometry**:
- sp^3d^2 corresponds to an octahedral geometry.
- In an octahedral structure, 4 bonds are in the plane, while 2 are above and below the plane.
- **Conclusion**: SF5^- is **not planar**.

3. **Analyze SF4**:
- **Valence Electrons Calculation**:
- Sulfur (S) has 6 valence electrons.
- Total for 4 Fluorine atoms = 6 + (7 × 4) = 6 + 28 = 34 electrons.
- **Electron Pairs Calculation**:
- Divide 34 by 2: 34 / 2 = 17 pairs.
- **Hybridization**:
- 5 pairs (4 bonding + 1 lone pair) indicate sp^3d hybridization.
- **Geometry**:
- sp^3d corresponds to a trigonal bipyramidal structure.
- In this structure, 3 bonds lie in the plane, while 2 are above and below the plane.
- **Conclusion**: SF4 is **not planar**.

4. **Analyze SOF4**:
- **Valence Electrons Calculation**:
- Sulfur (S) has 6 valence electrons.
- Oxygen (O) has 6 valence electrons.
- Total for 4 Fluorine atoms = 6 + 6 + (7 × 4) = 6 + 6 + 28 = 40 electrons.
- **Electron Pairs Calculation**:
- Divide 40 by 2: 40 / 2 = 20 pairs.
- **Hybridization**:
- 5 pairs (4 bonding + 1 lone pair) indicate sp^3d hybridization.
- **Geometry**:
- SOF4 has a structure where the 4 Fluorine atoms are in the plane, and the lone pair of electrons can also be considered in the plane.
- **Conclusion**: SOF4 is **planar**.

### Final Answer:
Among the compounds analyzed, **SOF4 is planar**.