Table of contents

1. A Review of General Chemistry5h 5m
2. Molecular Representations1h 14m
3. Acids and Bases2h 46m
4. Alkanes and Cycloalkanes4h 17m
5. Chirality3h 39m
6. Thermodynamics and Kinetics1h 22m
7. Substitution Reactions1h 48m
8. Elimination Reactions2h 30m
9. Alkenes and Alkynes2h 9m
10. Addition Reactions3h 19m
11. Radical Reactions1h 58m
12. Alcohols, Ethers, Epoxides and Thiols2h 42m
13. Alcohols and Carbonyl Compounds2h 17m
14. Synthetic Techniques1h 26m
15. Analytical Techniques:IR, NMR, Mass Spect7h 3m
16. Conjugated Systems6h 13m
17. Ultraviolet Spectroscopy51m
18. Aromaticity2h 34m
19. Reactions of Aromatics: EAS and Beyond5h 1m
20. Phenols55m
21. Aldehydes and Ketones: Nucleophilic Addition4h 56m
22. Carboxylic Acid Derivatives: NAS2h 51m
23. The Chemistry of Thioesters, Phophate Ester and Phosphate Anhydrides1h 10m
24. Enolate Chemistry: Reactions at the Alpha-Carbon1h 53m
25. Condensation Chemistry2h 9m
26. Amines1h 43m
27. Heterocycles2h 0m
28. Carbohydrates5h 53m
29. Amino Acids4h 20m
30. Peptides and Proteins2h 42m
31. Catalysis in Organic Reactions1h 30m
32. Lipids 2h 50m
33. The Organic Chemistry of Metabolic Pathways2h 52m
34. Nucleic Acids1h 32m
35. Transition Metals6h 14m
36. Synthetic Polymers1h 49m

1. A Review of General Chemistry

Sigma and Pi Bonds

Organic Chemistry

1. A Review of General Chemistry

Sigma and Pi Bonds

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3:53 minutes

Problem 41

Textbook Question

Which of the bonds in a carbon–oxygen double bond has more effective orbital–orbital overlap: the σ bond or the π bond?

Verified step by step guidance

Understand the nature of the bonds in a carbon–oxygen double bond. A double bond consists of one sigma (σ) bond and one pi (π) bond. The σ bond is formed by the head-on overlap of orbitals, while the π bond is formed by the side-by-side overlap of p orbitals.

Recall that the effectiveness of orbital–orbital overlap depends on the geometry of the interaction. Head-on overlap in a σ bond allows for greater overlap compared to the side-by-side overlap in a π bond.

Consider the orbitals involved in the σ bond. In a carbon–oxygen double bond, the σ bond is typically formed by the overlap of a sp² hybrid orbital from carbon and a sp² hybrid orbital from oxygen. These hybrid orbitals are oriented directly along the bond axis, maximizing overlap.

Now consider the orbitals involved in the π bond. The π bond is formed by the unhybridized p orbitals on carbon and oxygen, which are perpendicular to the bond axis. The side-by-side overlap of these p orbitals is less effective compared to the head-on overlap in the σ bond.

Conclude that the σ bond in a carbon–oxygen double bond has more effective orbital–orbital overlap than the π bond due to the geometry and type of orbital interaction involved.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Sigma (σ) and Pi (π) Bonds

Sigma (σ) bonds are formed by the head-on overlap of atomic orbitals, allowing for a strong bond with cylindrical symmetry around the bond axis. In contrast, pi (π) bonds result from the side-to-side overlap of p orbitals, which is generally weaker due to less effective overlap. Understanding the differences in formation and strength between these bond types is crucial for analyzing double bonds.

Orbital Overlap

Orbital overlap refers to the extent to which atomic orbitals from two atoms share space and interact when forming a bond. Greater overlap leads to stronger bonds. In a carbon-oxygen double bond, the σ bond has more effective overlap than the π bond, which is essential for understanding the stability and reactivity of such bonds in organic compounds.

Bond Strength and Stability

The strength and stability of a bond are influenced by the type of bonds present and their respective overlaps. Sigma bonds are generally stronger and more stable than pi bonds due to their effective overlap. In a carbon-oxygen double bond, the presence of both σ and π bonds means that while the σ bond provides significant stability, the π bond contributes to the overall reactivity of the molecule.

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