Sigma (s) Bond

Sigma (s) Bond Definition:

The Sigma (s or σ) bond is a covalent bond formed between two atoms, which is characterized by circular symmetry with respect to the bond axis

Sigma (s) Bond  Explained:

A sigma bond is thus, a bond wherein the maximum density of the electron cloud is along the axis connecting the centers of the two participating atoms. It represents a strong overlap and can be thought of as a head-on collision of the orbitals.

Note :

  • All single bonds are sigma bonds.
  • Sigma bonds are stronger than pi bonds.
  • Sigma bonds may arise from the overlap between s, p, and d orbitals, like s – s orbitals, s – p orbitals, p – p orbitals, s – d orbitals, and so on.
  • s orbitals are spherical in shape, while p and d orbitals are dumbbell shaped. Therefore, the s – s over lap is weaker compared to the s – p or p – p overlap.

Examples –

*to visualize the circular symmetry, imagine slicing the bond at the bonding location. The cross-section with respect to the bond axis will be circular.