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Planarity of Organic Molecules (CIE AS Chemistry)

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Planar Molecules

  • Planar molecules have all their atoms in the same plane
    • Eg. linear, bent, trigonal planar and square planar

 Examples of planar molecules

An Introduction to AS Level Organic Chemistry Planar Molecules, downloadable AS & A Level Chemistry revision notes

The diagram shows molecules which have all their atoms in the same plane with their name and the associated bond angle

  • The presence of an sp2 hybridised carbon can force the molecule to adopt a planar configuration (trigonal planar)
  • The 3 σ bonds position themselves in a trigonal planar position so that the bonding pair of electrons are as far away from each other and therefore minimise the repulsion between them

The planarity of ethene

 An Introduction to AS Level Organic Chemistry Planar Ethene, downloadable AS & A Level Chemistry revision notes

Ethene is a planar molecule with two trigonal planar centres around the carbon atoms

The planarity of propene

An Introduction to AS Level Organic Chemistry Planar Propene, downloadable AS & A Level Chemistry revision notes

Propene has two trigonal planar centres around the carbon-carbon double bond and one tetrahedral centre

  • The presence of an sp hybridised carbon can also force the molecule to adopt a planar configuration (linear)
  • The 2 σ bonds position themselves in a linear position to minimise the repulsion between the bonding pairs of electrons

The planarity of ethyne

 An Introduction to AS Level Organic Chemistry Planar Ethyne, downloadable AS & A Level Chemistry revision notes

Ethyne is a planar molecule with one planar centre: the molecule is linear

The planarity of propyne 

An Introduction to AS Level Organic Chemistry Planar Propyne, downloadable AS & A Level Chemistry revision notes

Propyne has one planar centre around the carbon-carbon triple bond (linear) and one tetrahedral centre

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Philippa

Author: Philippa

Expertise: Chemistry

Philippa has worked as a GCSE and A level chemistry teacher and tutor for over thirteen years. She studied chemistry and sport science at Loughborough University graduating in 2007 having also completed her PGCE in science. Throughout her time as a teacher she was incharge of a boarding house for five years and coached many teams in a variety of sports. When not producing resources with the chemistry team, Philippa enjoys being active outside with her young family and is a very keen gardener.