Electron Density Distribution of Ethyne Molecule Triple Bond

Sp hybridization is used to describe ethylene (acetylene) molecule. In order to establish a bond between the carbon atoms, two sp orbitals are overlapped to form a σ-bond and then the remaining four non-hybrid p-orbitals are overlapped to form two π-bonds (the distribution of the π-bonds electrons forms a cylindrical structure around the bond). A triple bond is formed by one σ-bond and two π-bonds.

When a bond is formed between the carbon atom and the hydrogen atom, sp and s-orbital are overlapped to form the σ-bonds (simple bonds are formed).