Question

What is the electron-pair and molecular geometry around the central S atom in sulfuryl chloride, \(\mathrm{SO}_{2} \mathrm{Cl}_{2} ?\) What is the hybridization of sulfur in this compound?

Short answer

The electron-pair and molecular geometry are tetrahedral, and the hybridization of sulfur is \(sp^3\).

Step-by-step solution

Count Valence Electrons

Sulfur (S) has 6 valence electrons, oxygen (O) has 6 each, and chlorine (Cl) has 7 each. Since there are two oxygens and two chlorines, the total number of valence electrons is: \(6 + 2 \times 6 + 2 \times 7 = 32\) electrons.

Draw Lewis Structure

In the Lewis structure for \(\mathrm{SO}_{2}\mathrm{Cl}_{2}\), sulfur is the central atom with two double-bonded oxygens and two single-bonded chlorines, resulting in no lone pairs on sulfur. Each oxygen forms a double bond with sulfur, consuming 4 electrons each, and each chlorine forms a single bond with sulfur, consuming 2 electrons each. This uses up the 32 available electrons.

Determine Electron-Pair Geometry

The geometry around sulfur is based on the regions of electron density. Sulfur is surrounded by four regions (two double bonds with oxygen and two single bonds with chlorine), leading to a tetrahedral electron-pair geometry.

Determine Molecular Geometry

Since all four regions are bonds (no lone pairs on sulfur), the molecular geometry is also tetrahedral. Each bond pair repels equally, resulting in the tetrahedral shape.

Find Hybridization of Sulfur

Based on the tetrahedral electron-pair geometry, sulfur is \(sp^{3}\) hybridized, combining one s orbital with three p orbitals, to form four equivalent \(sp^{3}\) hybrid orbitals.

Key concepts

Valence Electrons

Valence electrons are the outermost electrons of an atom that participate in chemical bonding. They play a critical role in determining how atoms bond with each other. For sulfuryl chloride (\(\mathrm{SO}_{2} \mathrm{Cl}_{2} \)), understanding the valence electrons is vital to constructing its Lewis structure.

Sulfur has 6 valence electrons, each oxygen atom contributes 6 valence electrons, and each chlorine atom provides 7 valence electrons. Since \(\mathrm{SO}_{2} \mathrm{Cl}_{2} \) consists of one sulfur, two oxygen atoms, and two chlorine atoms, the total count of valence electrons can be calculated as follows:

• Sulfur: 6 electrons
• Oxygen: 2 × 6 = 12 electrons
• Chlorine: 2 × 7 = 14 electrons

Adding these together gives a total of 32 valence electrons. These electrons must be distributed around the atoms in the molecule to achieve a stable structure.

By counting valence electrons accurately, it helps in arranging atoms in the Lewis structure properly.

Lewis Structure

The Lewis structure is a way of representing molecules showing all valence electrons around atoms as dots or lines for bonds. For sulfuryl chloride (\(\mathrm{SO}_{2} \mathrm{Cl}_{2} \)), the structure includes bonds from sulfur to oxygen and chlorine atoms.

Sulfur is positioned at the center of the molecule due to its ability to form multiple bonds and being less electronegative compared to oxygen and chlorine. In the Lewis structure:

• Each oxygen forms a double bond with sulfur, utilizing 4 electrons for each bond.
• Each chlorine forms a single bond with sulfur, using 2 electrons per bond.

This arrangement results in sulfur being bonded to two oxygens and two chlorines, creating the complete structure without any lone pairs on the sulfur atom. The total electrons used, 32, equal the counted valence electrons, ensuring all atoms achieve stable electron configurations.

Constructing an accurate Lewis structure is crucial because it provides the framework for determining the molecule’s geometry and hybridization.

Electron-Pair Geometry

Electron-pair geometry, also known as electron-group geometry, considers all regions of electron density around a central atom, including lone pairs and bonds. For sulfuryl chloride (\(\mathrm{SO}_{2} \mathrm{Cl}_{2} \)), the electron-pair geometry centers around sulfur.

The sulfur atom in \(\mathrm{SO}_{2} \mathrm{Cl}_{2} \) is surrounded by four regions of electron density. These are the two double bonds with oxygen and the two single bonds with chlorine. Though these bonds differ in type, they all count as one region each.

With four regions around sulfur, the electron-pair geometry adopts a tetrahedral configuration. The tetrahedral shape arises because electron pairs distribute themselves to minimize repulsion, resulting in bonded electron regions being as far apart as possible. This geometric arrangement is crucial for predicting the molecular geometry and understanding the molecular shape.

Molecular Geometry

Molecular geometry focuses solely on the arrangement of atoms around the central atom, ignoring lone pairs. For sulfuryl chloride (\(\mathrm{SO}_{2} \mathrm{Cl}_{2} \)), the molecular geometry is determined based on the positions of all atoms bonded to sulfur.

As established in the electron-pair geometry, sulfur is surrounded by four equivalent bond pairs—two double bonds with oxygen and two single bonds with chlorine. Since there are no lone pairs on sulfur, all four regions are bonding pairs.

This setup results in a molecular geometry that is also tetrahedral. The tetrahedral structure means that the sulfur atom is positioned at the center of a tetrahedron, with each bond angle ideally at approximately 109.5°. Such geometry ensures that all repulsions between bonding pairs are minimized, leading to a very stable arrangement.

Understanding the molecular geometry of a compound like \(\mathrm{SO}_{2} \mathrm{Cl}_{2} \) is vital in predicting its physical and chemical behaviors.

Hybridization

Hybridization is the concept of intermixing atomic orbitals to create new hybrid orbitals suitable for the pairing of electrons to form chemical bonds. For sulfur in sulfuryl chloride (\(\mathrm{SO}_{2} \mathrm{Cl}_{2} \)), hybridization helps explain the bonding and geometry.

Sulfur here is hybridized as \(\mathrm{sp}^{3} \), combining one s orbital and three p orbitals. This hybridization correlates with the tetrahedral electron-pair geometry observed.

The \(\mathrm{sp}^{3} \) hybridization results in four equivalent hybrid orbitals radiating from the sulfur atom, which are used to form sigma bonds with oxygen and chlorine atoms. This consistent bonding setup ensures all bonds are equivalent and positioned geometrically to minimize electron repulsion.

Hybridization is essential for understanding the complement of molecular geometry and electron distribution in covalent compounds.