Among the carbon-halogen bonds, the carbon-iodine (C-I) bond typically has the lowest bond enthalpy. Generally, the bond enthalpy decreases as you move down the halogen group from fluorine to iodine. This trend arises due to the increasing atomic size of the halogens, which results in weaker bonding interactions with carbon. Consequently, the C-I bond has a lower bond enthalpy compared to carbon bonds with smaller halogens such as carbon-fluorine (C-F), carbon-chlorine (C-Cl), or carbon-bromine (C-Br) bonds.