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Methyl Group vs. Methylene Group: What's the Difference?

Edited by Aimie Carlson || By Janet White || Published on February 12, 2024
A methyl group is a -CH₃ group, a carbon atom bonded to three hydrogens. A methylene group is a -CH₂- group, a carbon atom bonded to two hydrogens and attached to other atoms or groups.

Key Differences

A methyl group, -CH₃, consists of one carbon atom bonded to three hydrogen atoms. In contrast, a methylene group, -CH₂-, features a carbon atom bonded to two hydrogen atoms and connected to other carbon atoms or groups.
The methyl group is a common alkyl group in organic chemistry, often found as a branch in larger molecules. Methylene groups, however, are part of the backbone in many organic compounds, linking various parts of a molecule.
Methyl groups are stable and generally non-reactive, influencing the physical and chemical properties of compounds. Methylene groups are more reactive, often participating in chemical reactions like addition or polymerization.
In methyl groups, the carbon atom achieves a tetrahedral geometry, leading to nonpolarity in molecules. Methylene groups, however, can influence the polarity and shape of molecules, depending on their placement.
Methyl groups can be introduced into molecules via methylation reactions, impacting solubility and reactivity. Methylene groups are key in forming double bonds or rings in organic structures, affecting stability and reactivity.

Comparison Chart


One carbon, three hydrogens
One carbon, two hydrogens


Usually attached to another carbon
Links carbon atoms or groups


Generally non-reactive
More reactive

Impact on Molecular Shape

Little effect on shape
Can change the shape and polarity

Chemical Role

Alters physical properties
Key in forming structures like rings

Methyl Group and Methylene Group Definitions

Methyl Group

A common substituent in organic compounds, affecting solubility.
Adding a methyl group changed the compound's boiling point.

Methylene Group

A fundamental building block in complex organic structures.
Polyethylene is composed of repeating methylene groups.

Methyl Group

A non-polar alkyl group often found in organic molecules.
Methyl groups are commonly seen in pharmaceutical compounds.

Methylene Group

A group in organic compounds with one carbon atom bonded to two hydrogens.
The methylene group is a key component in the structure of ethylene.

Methyl Group

A group in organic chemistry with one carbon atom bonded to three hydrogens.
The presence of a methyl group can make a compound more hydrophobic.

Methylene Group

A bridge-like structure connecting carbon atoms in organic molecules.
Methylene groups form the backbone of many polymers.

Methyl Group

A simple hydrocarbon group, symbolized as -CH₃.
Ethane consists of two carbon atoms, each with a methyl group.

Methylene Group

A reactive component in organic chemistry, participating in addition reactions.
Methylene groups are reactive sites in unsaturated hydrocarbons.

Methyl Group

A basic unit in organic chemistry, influencing molecular structure.
The molecule's reactivity was altered by the addition of a methyl group.

Methylene Group

A versatile group influencing the formation of double bonds and rings.
Cyclohexane's ring structure is made of methylene groups.


How does a methylene group influence molecular structure?

It forms the backbone of molecules and can influence shape and polarity.

How does methylation impact a molecule?

It can change physical properties like boiling point and reactivity.

What is a methyl group?

It's a -CH₃ group, with one carbon atom bonded to three hydrogens.

Do methylene groups participate in addition reactions?

Yes, they are reactive and can engage in such chemical reactions.

Where is a methyl group commonly found?

In various organic compounds as a stable, non-reactive branch.

What role does a methylene group play in polymerization?

It's a reactive site, crucial in linking monomers to form polymers.

Are methylene groups involved in forming hydrocarbon chains?

Yes, they link carbon atoms to form chains in hydrocarbons.

What does a methylene group represent?

A -CH₂- group, with one carbon bonded to two hydrogens, connecting other atoms.

Are methyl groups reactive?

They are generally less reactive compared to other groups.

Is the methylene group found in rings and double bonds?

Yes, it's key in forming these structures in organic chemistry.

Do methyl groups affect the polarity of a molecule?

They generally do not have a significant impact on polarity.

Can methyl groups be added to existing compounds?

Yes, through methylation reactions.

Can a compound have multiple methyl groups?

Yes, compounds can have more than one methyl group.

Can methylene groups be converted to other functional groups?

Yes, they can be chemically modified to form different functional groups.

Can the presence of a methyl group affect solubility?

Yes, it can increase hydrophobicity, affecting solubility in water.

What is the significance of methylene groups in organic rings?

They are crucial in maintaining the stability and structure of rings.

What types of compounds contain methylene groups?

They are found in a wide range of compounds, including hydrocarbons and polymers.

What's the difference in the geometric structure between methyl and methylene groups?

Methyl groups have a tetrahedral geometry, while methylene groups' geometry depends on their bonding context.

How does a methyl group affect the boiling point of a compound?

It can increase the boiling point due to increased molecular weight.

How does the reactivity of methylene groups benefit chemical synthesis?

Their reactivity allows for various chemical transformations in synthesis.
About Author
Written by
Janet White
Janet White has been an esteemed writer and blogger for Difference Wiki. Holding a Master's degree in Science and Medical Journalism from the prestigious Boston University, she has consistently demonstrated her expertise and passion for her field. When she's not immersed in her work, Janet relishes her time exercising, delving into a good book, and cherishing moments with friends and family.
Edited by
Aimie Carlson
Aimie Carlson, holding a master's degree in English literature, is a fervent English language enthusiast. She lends her writing talents to Difference Wiki, a prominent website that specializes in comparisons, offering readers insightful analyses that both captivate and inform.

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