Geometry and Bonding: Data Sheet sulfur dichloride, SCI
# valence electrons: Lewis structure: hydronium ion, H
O
valence electrons: Lewis structure (indicate formal charges): Geometry description: Polar or Non-polar: Hybridization of central atom: Description of bonds within the molecule (pi or sigma): Geometry description: Polar or Non-polar: Hybridization of central atom: Description of bonds within the molecule (pi or sigma): Draw the molecule with the correct shape. If the molecule is polar, indicate the dipole moment using the correct notation. Draw the molecule with the correct shape. If the molecule is polar, indicate the dipole moment using the correct notation.
The Correct Answer and Explanation is:
Sulfur Dichloride (SCl₂)
Valence Electrons:
Sulfur has 6 valence electrons.
Chlorine has 7 valence electrons × 2 = 14
Total = 6 + 14 = 20 valence electrons
Lewis Structure:
The sulfur atom is the central atom, with two single bonds connecting to each chlorine atom and two lone pairs on the sulfur. Each chlorine has three lone pairs.
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Cl – S – Cl
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Geometry Description:
The molecule adopts a bent (V-shaped) geometry due to the two lone pairs on sulfur, which repel the bonding pairs.
Polar or Non-polar:
Polar – The bent shape and difference in electronegativity between sulfur and chlorine lead to a net dipole moment.
Hybridization of Central Atom:
sp³ – The sulfur has four regions of electron density (2 bonds and 2 lone pairs).
Description of Bonds:
All S–Cl bonds are sigma bonds. There are no pi bonds.
Dipole Moment Notation:
The dipole points from sulfur toward each chlorine, but due to the asymmetrical shape, a net dipole remains.
Hydronium Ion (H₃O⁺)
Valence Electrons:
Oxygen has 6 valence electrons
Hydrogen has 1 × 3 = 3
Subtract 1 electron due to the positive charge
Total = 6 + 3 – 1 = 8 valence electrons
Lewis Structure with Formal Charges:
Oxygen is the central atom with three single bonds to hydrogen and one lone pair. The positive charge is delocalized, but oxygen bears it due to having only one lone pair.
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H – O⁺ – H
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Geometry Description:
The geometry is trigonal pyramidal, similar to ammonia (NH₃), due to the lone pair.
Polar or Non-polar:
Polar – Asymmetry caused by the lone pair and the polar O–H bonds create a net dipole.
Hybridization of Central Atom:
sp³ – Four electron domains (three bonds and one lone pair)
Description of Bonds:
All O–H bonds are sigma bonds.
Dipole Moment Notation:
The dipole points from the hydrogens toward the oxygen due to oxygen’s higher electronegativity.
Explanation
Understanding molecular geometry and bonding begins with counting valence electrons. For sulfur dichloride (SCl₂), sulfur contributes 6 and each chlorine 7, totaling 20 electrons. Two electrons are used for each of the S–Cl bonds (4 total), and the remaining 16 are distributed as lone pairs—6 on each chlorine and 4 on sulfur. The resulting shape is bent due to two lone pairs on sulfur repelling bonding pairs, making the molecule polar as the dipoles from each S–Cl bond do not cancel out.
SCl₂’s central sulfur atom has four electron groups (two bonding and two non-bonding), giving it sp³ hybridization. The bonds in SCl₂ are sigma bonds, formed by head-on overlap of orbitals. No pi bonds exist in this molecule since there are no multiple bonds.
For the hydronium ion (H₃O⁺), we begin with 6 electrons from oxygen and 3 from hydrogen, then subtract one for the positive charge. With 8 total electrons, oxygen forms three sigma bonds with hydrogen atoms and retains one lone pair. The resulting shape is trigonal pyramidal due to lone pair repulsion, making the molecule polar. The dipole moment is directed from the hydrogen atoms toward the more electronegative oxygen.
The central oxygen also has sp³ hybridization—four regions of electron density (three bonding pairs and one lone pair). Like SCl₂, all bonds in H₃O⁺ are sigma bonds.
Polarity in both molecules is caused by their asymmetrical shapes and differences in electronegativity. These factors influence the physical and chemical properties such as solubility, reactivity, and intermolecular forces. Understanding the electron geometry, molecular geometry, and bond types helps predict molecular behavior in different environments.
