Sigma (σ) Bond Sigma bond is in the same axis as the axis between the nuclei of bonding atoms. The sp3 term refers to a hybrid (combination) of one s-orbital and 3 p-orbitals.
The Tetrahedron The tetrahedral shape is the most efficient way to arrange the four sp3 orbitals.
Sigma Bonding in Methane The sigma bond is formed when the electron in the sp3 orbital joins with another electron in a s-orbital. Eg. Methane
sp2Hybridisation We now have hybridisation of one s-orbital and two p-orbitals.
sp2Hybridisation Becomes Pi Bond Become sigma bonds
Pi (π) Bonding in Ethane The bond forms above and below the axis of bonding
The Pi Bond Cannot Rotate Build a model to show the abilty of the single bond to rotate. Build a model to show the inability of the double bond to rotate.