Question

Dimethyl sulfoxide, also known as DMSO, is an important organic solvent often used for drug delivery since it readily penetrates the skin. Look up the formula for DMSO and write the Lewis dot structure. (Hint: There are no \(\mathrm{C}-\mathrm{C}\) bonds in the molecule.)

Short answer

DMSO is C2H6OS; S is central, double-bonded to O, single-bonded to two methyl groups with lone pairs on S and O.

Step-by-step solution

Determine the Molecular Formula

The formula for dimethyl sulfoxide (DMSO) is C2H6OS. This can be confirmed with a quick search online or using a chemistry resource.

Identify the Central Atom

In DMSO, the central atom is the sulfur (S) atom due to its ability to form multiple bonds.

Arrange the Atoms

Place the sulfur atom in the center. Attach the two carbon (C) atoms to the sulfur via single bonds, ensuring there are no direct carbon-to-carbon bonds as mentioned in the hint.

Attach the Hydrogen Atoms

Each carbon atom (in the methyl group) is bonded to three hydrogen (H) atoms. So attach three H atoms to each of the C atoms.

Complete the Structure with Lone Pairs and Double Bonds

Since sulfur can hold more than 8 electrons in its valence shell, add a lone pair on the sulfur atom and form a double bond with the oxygen. Thus, the oxygen bonds to sulfur, completing the octet for both the oxygen and sulfur atoms.

Draw the Lewis Dot Structure

Represent the bonds using lines between atoms (one line representing a single bond) and add dots to show lone pairs on oxygen and sulfur. The final structure should have sulfur double-bonded to oxygen and single-bonded to two methyl groups.

Key concepts

Dimethyl Sulfoxide

Dimethyl sulfoxide, commonly referred to as DMSO, is an intriguing molecule due to its unique characteristics and widespread usage, particularly as an organic solvent.
This colorless liquid is well known for its ability to penetrate biological membranes, which is why it is frequently employed in pharmaceutical formulations and drug delivery systems.

• DMSO's solubility in both polar and nonpolar solvents makes it exceptionally versatile.
• It is known for reducing pain and inflammation, although its exact mechanism in these areas is still under investigation.
• In chemical research, DMSO is utilized as a reaction medium because it can dissolve a wide range of substances, greatly aiding in the synthesis of various compounds.

Understanding DMSO's interaction with other molecules begins with its Lewis dot structure, which reveals how atoms bond and share electrons.

Molecular Formula

The molecular formula of dimethyl sulfoxide is particularly interesting: it is represented as \( ext{C}_2 ext{H}_6 ext{OS} \).

• The formula signifies that the molecule contains two carbon (C) atoms, six hydrogen (H) atoms, one oxygen (O) atom, and one sulfur (S) atom.
• This composition suggests a simple yet unique arrangement of atoms, highlighted by the fact there are no carbon-to-carbon bonds within the molecule.

Molecular formulas are succinct forms to describe the composition and structure of a molecule, indicating not just the kind and number of atoms, but also hinting at the possible arrangement based on known bonding patterns and atom valency.

Central Atom

The concept of a 'central atom' in Lewis structures is notably crucial to understanding how molecules are constructed.
In dimethyl sulfoxide, the central atom is the sulfur (S) atom.

• Sulfur serves as the core of the molecule due to its ability to form multiple bonds, accommodating more than the typical octet of electrons around it.
• In DMSO, sulfur holds the molecule together by binding to two methyl groups and an oxygen atom.

Identifying the central atom is an essential step in constructing a Lewis dot structure, as it usually has the greatest bonding potential and defines the molecule's geometry.

Organic Solvent

Organic solvents like dimethyl sulfoxide play a vital role in both laboratory and industrial chemistry settings.
They are used to dissolve other substances, allowing chemical reactions to occur more readily.

• DMSO is valued as an organic solvent because it can dissolve a wide variety of organic and inorganic substances, which makes it very handy for researchers and industrial chemists.
• The solvent properties of DMSO allow for its use in the manufacture of polymers, coatings, and pharmaceuticals.
• Its miscibility with water and many organic solvents further adds to its utility, widening the spectrum of its applications.

Due to these properties, understanding DMSO's Lewis dot structure not only provides insight into its chemical nature but also underscores why it functions so effectively as a solvent.