Draw the Lewis structure of SF2 showing all lone pairs. What is the hybridization of the central atom? Identify the molecular geometry of SF2. What is the approximate bond angle in SF2?
The Correct Answer and Explanation is :
The Lewis structure of sulfur difluoride (SF₂) is drawn as follows:
- Total Valence Electrons: Sulfur (S) has 6 valence electrons, and each fluorine (F) has 7 valence electrons. Therefore, the total number of valence electrons is:
[
6 \, (\text{from S}) + 2 \times 7 \, (\text{from F}) = 20 \, \text{electrons}.
] - Bonding: Place sulfur in the center and connect each fluorine atom to sulfur with a single bond. This uses 4 electrons (2 electrons per bond).
- Distribute Remaining Electrons: After forming the bonds, 16 electrons remain. These are placed as lone pairs around the fluorine atoms first, to satisfy the octet rule for fluorine. Each fluorine atom gets 3 lone pairs, consuming 12 electrons.
- Remaining Electrons on Sulfur: After the fluorine atoms have their lone pairs, 4 electrons remain, which are placed as lone pairs on sulfur. This gives sulfur two lone pairs.
The final Lewis structure is:
F
|
F—S—F
|
:Where : represents a lone pair of electrons on sulfur and fluorine.
Hybridization of the Central Atom
The central sulfur atom in SF₂ has two single bonds with fluorine atoms and two lone pairs of electrons. This results in four regions of electron density around sulfur. According to VSEPR (Valence Shell Electron Pair Repulsion) theory, four regions of electron density around the central atom indicate sp³ hybridization.
Molecular Geometry
The molecular geometry of SF₂ is bent. This is because the two lone pairs on sulfur push the fluorine atoms closer together, resulting in a bond angle that is less than the ideal 109.5° of a perfect tetrahedral geometry. The repulsion between the lone pairs is greater than the repulsion between bonding pairs, leading to a bent shape.
Approximate Bond Angle
The bond angle in SF₂ is approximately 98°. This is due to the lone pairs on the central sulfur atom, which distort the bond angle from the ideal 109.5° in a tetrahedral arrangement.
Conclusion
In summary, the Lewis structure of SF₂ shows sulfur at the center with two bonds to fluorine atoms and two lone pairs on sulfur. The hybridization of sulfur is sp³, and the molecular geometry is bent, with an approximate bond angle of 98°.