Draw the Lewis structure for CH3S(O)CH3

Draw the Lewis structure for CH3S(O)CH3, a neutral molecule.

The correct answer and explanation is :

Lewis Structure of CH₃S(O)CH₃ (Dimethyl Sulfoxide, DMSO)

1. Step 1: Count Valence Electrons

• Carbon (C): 4 valence electrons × 2 = 8
• Hydrogen (H): 1 valence electron × 6 = 6
• Sulfur (S): 6 valence electrons × 1 = 6
• Oxygen (O): 6 valence electrons × 1 = 6
• Total valence electrons = 26

1. Step 2: Arrange the Atoms

• Carbon is less electronegative than sulfur, so the two carbon atoms are bonded to sulfur.
• Oxygen is more electronegative and is bonded to sulfur.

1. Step 3: Draw Single Bonds

• Each carbon is bonded to three hydrogen atoms and the sulfur atom.
• Sulfur is bonded to oxygen with a double bond (to satisfy the octet rule).

1. Step 4: Assign Lone Pairs

• Oxygen has two lone pairs.
• Sulfur has one lone pair (since it forms three bonds: one to each methyl group and one to oxygen).

Final Lewis Structure

        H   H
        |   |
    H—C—S—O
        |   ||
        C   ..
        |   
        H  

Explanation (300 words)

Dimethyl sulfoxide (DMSO, CH₃S(O)CH₃) is a neutral molecule with a sulfur-oxygen double bond and two methyl (CH₃) groups. The Lewis structure follows the octet rule, ensuring that all atoms have a stable electron configuration.

Sulfur’s Bonding and Hybridization
Sulfur in DMSO has an oxidation state of +2 and adopts a trigonal pyramidal geometry due to its lone pair. The S=O bond is polar, as oxygen is more electronegative than sulfur, resulting in a partial negative charge on oxygen and a partial positive charge on sulfur. The methyl groups provide non-polar characteristics to the molecule, making DMSO a useful solvent for both polar and non-polar compounds.

Resonance Considerations
While sulfur can theoretically form an expanded octet, DMSO is best represented with a double bond between sulfur and oxygen, with no significant resonance forms involving single bonds. The S=O bond has some double bond character due to p-π conjugation, where oxygen’s lone pair interacts with sulfur’s empty d-orbitals.

Molecular Polarity and Applications
DMSO is polar due to the S=O dipole moment and is widely used as an industrial solvent because it dissolves both organic and inorganic compounds. It also has medical applications, such as in drug delivery systems.

This Lewis structure accurately represents the bonding and electronic distribution in DMSO, ensuring all atoms satisfy the octet rule while reflecting the molecular geometry and polarity.