How may possible `angle FSeF` bond angles are present in `SeF_(4)` molecule ?

Answer

To determine the possible bond angles in the SeF₄ molecule, we can follow these steps:

### Step 1: Identify the central atom and its valence electrons
- Selenium (Se) is the central atom in SeF₄. It belongs to Group 16 of the periodic table, which means it has 6 valence electrons.

### Step 2: Determine the number of bonds and lone pairs
- In SeF₄, selenium forms 4 bonds with fluorine atoms. This accounts for 4 of its 6 valence electrons.
- The remaining 2 valence electrons will form 1 lone pair on the selenium atom.

### Step 3: Calculate the steric number
- The steric number is calculated as the number of bonded atoms plus the number of lone pairs. Here, we have 4 bonded fluorine atoms and 1 lone pair:
\[ \text{Steric Number} = 4 \text{ (F atoms)} + 1 \text{ (lone pair)} = 5 \]

### Step 4: Determine hybridization and molecular geometry
- A steric number of 5 indicates that the hybridization of selenium in SeF₄ is sp³d.
- The molecular geometry corresponding to sp³d hybridization is trigonal bipyramidal.

### Step 5: Identify the shape of the molecule
- With one lone pair, the shape of SeF₄ is described as seesaw.

### Step 6: Identify possible bond angles
- In a trigonal bipyramidal geometry, there are several bond angles:
- The angles between the equatorial fluorine atoms (F1, F2, and F3) are 120°.
- The angles between the axial fluorine atoms (F4) and the equatorial fluorine atoms are 90°.

### Step 7: Count the unique bond angles
- The unique bond angles in SeF₄ are:
1. F1-Se-F2
2. F1-Se-F3
3. F1-Se-F4
4. F2-Se-F3
5. F2-Se-F4
6. F3-Se-F4

Thus, there are a total of **6 possible FSeF bond angles** in the SeF₄ molecule.

### Final Answer
The possible FSeF bond angles present in SeF₄ are **6**.

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