Double and triple bonds

Double bond C=C

   

                                                                   Sp² Hybrid orbitals overlap

                                                                    Forming sigma bond

                                 Unhybridised p orbitals overlap

                                   To form a pi bond. Note that the

                                                                  pi Bond has a lobe above and

                                      below the Sigma bond. However,

                               it still Constitutes One bond.

                                        The C=C double bond is Therefore,

                              one sigma and one pi bond.

        

                 Triple bond C=_C

                                                                                  pz and py unhybridised

                                                                               orbitals overlap to form

                                                                                two pi bonds. 

 sp hybrid orbitals overlap to form                      The triple bond is therefore

 a sigma bond.                                                       Two pi bonds and one sigma bond.