Chapter 11.2: Modes of Orbital Overlap and the Types of Covalent Bonds

Flashcards from Chapter 11.2 of Chemistry: The Molecular Nature of Matter and Change.

Sigma bond (σ bond)

A bond formed by the end-to-end overlap of orbitals, with highest density along the bond axis

• Includes all single bonds

Pi bond (π bond)

A bond formed by the side-to-side overlap of orbitals, increasing electron density between two nuclei

• Includes the bonds formed after a single σ bond, such as double and triple bonds

• Has two equally-occupied lobes of electron density, above and below the σ bond axis

• Utilizes the unhybridized p orbitals, but is weaker due to less overlap

Free rotation

This is permitted in σ bonds due to overlap not being affected

Restricted rotation

This occurs in π bonds (if trying to rotate just one atom) due to overlap being reduced

• Results in the creation of distinct isomeric structures for certain molecules