• # question_answer 36) Distinguish between a sigma bond and a pi bond

COMPARISON OF SIGMA AND PI-BONDS S. No. $\sigma$-bond $\pi$-bond (i) The bond is formed by the overlapping of orbitals along their axes (end to end overlap). It includes s-s, s-p and p-p overlapping. The bond is formed by sidewise overlapping of orbitals (lateral overlapping). It includes p-p overlapping. (ii) It is a strong bond. It is a weak bond. (iii) Electron cloud is symmetrical about the line joining the two nuclei. Electron cloud is unsymmetrical. (iv) There can be free rotation of atoms around this bond. Free rotation is not possible around this bond. (v) These are less reactive. These are more reactive. (vi) The shape of the molecule is determined by these bonds. These bonds do not affect the shape of the molecule. (vii) $\sigma$-electrons are referred as localized. $\pi$-electrons are referred as mobile electrons. (viii) $\sigma$-bond can have an independent existence. $\pi$-bond always exists along with a $\sigma$-bond.