Chemistry A-Level
Free rotation about σ-bonds
What Free rotation about σ-bonds means in Chemistry A-Level, as defined for OCR.
Definition of Free rotation about σ-bonds
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Reference: OCR
Because the σ-bond electron density is symmetrical about the bond axis, rotation about a C–C σ-bond does not break the bond, so the groups can rotate freely relative to one another.
Topics that use Free rotation about σ-bonds
- Alkanes (OCR A-Level)
Related terms
- Bond angle of about 109.5°
- Consequences for alkane reactivity
- Distinguishing σ-bonds from π-bonds
- Effect of branching on boiling point
- Effect of carbon-chain length on boiling point
- Electron pair repulsion between bonding pairs
- Further substitution giving polyhalogenated products
- Incomplete combustion products
Using Free rotation about σ-bonds in the exam
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