Electron Density Distribution of Ethane Molecule Single Bond

The hybridization of sp³ orbital is used to describe the ethane molecule. When bonding between carbon atoms occurs, a pair of sp³ orbitals are formed on the junction of the cores to form the σ-bond. A simple bond is formed, which is always one σ-bond.

During the bonding between a carbon atom and a hydrogen atom, the sp³ orbital and the s-orbital are overlapped to form the σ-bonds (simple bonds are formed).