The CC bonding is analyzed using dynamic orbital forces (DOF) in the series cyclopropane‐ethane‐ benzene‐ethylene‐acetylene. The sum Σ(DOF)t of the DOF over occupied molecular orbitals (MOs) is found linearly correlated to bond energies and thus can be used as a tool for determination of CC bond strength. A partition of bonding into σ and π components indicates a weakening of the σ bonding along the series, mainly due to the decrease of the bonding character of the highest σ MO. For C2 molecule, Σ(DOF) t was computed taking into account the four dominant configurations. On the basis of the preceding correlation, the C2 bond was found about 15 kcal/mol weaker than that of acetylene, with a 25% σ participation; the bond order of C2 can be evaluated at about 2.8 if we assume bond orders of 3 for acetylene and 2 for ethylene. Some sila homologs of the preceding carbon compounds have been studied. They exhibit characteristics generally close to the carbon compounds. A quite good correlation between Σ(DOF)t and bond energies is also observed.