Resonance structures

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Definition

Two or more Lewis structures that together represent the bonding in a molecule whose electrons are actually delocalised. The real molecule is a hybrid of these structures, which explains its stability, as in benzene.

Worked examples

The carbonate ion \(\)CO\(_3^{2-}\) has three resonance structures, each with a double bond to a different oxygen atom.

The actual ion has all three C–O bonds identical and intermediate in length, not three separate forms.

Benzene \(\)C\(_6\)H\(_6\) has two resonance structures with alternating single and double bonds in opposite positions.

The real benzene ring has six equal C–C bonds; resonance explains its unusual stability.

Common mistakes

The molecule flips back and forth between resonance structures. → The molecule is always a single hybrid; resonance structures are just drawings we use. Resonance structures are not real separate forms — they're a notation tool to show delocalised electrons.
Drawing one resonance structure is enough to show the bonding. → All resonance structures together represent the true electron distribution. One structure alone incorrectly suggests electrons are localised in specific bonds.
Resonance structures have different atom positions. → Only electrons move between resonance structures; atoms stay in the same positions. Changing atom positions would be a different molecule, not a resonance structure.

Where you'll use it next

You'll use resonance structures when studying organic chemistry mechanisms, predicting molecule stability, understanding aromatic compounds, and explaining acidity and reactivity patterns in advanced chemistry courses.

Found in 1 StudyPug lesson

Understanding Conjugation in Organic Chemistry

Organic Chemistry

Explore the fundamental concepts of conjugation and resonance structures in organic chemistry. Learn how these principles influence molecular stability, reactivity, and properties to excel in your studies.

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