The bond dissociation energy of B−F in BF3 is 646 kJ mol⁻¹, whereas that of C−F in CF4 is 515 kJ mol⁻¹. The correct reason for higher B−F bond dissociation energy as compared to that of C−F is:

Boron in BF3 has a vacant p−orbital, allowing back bonding while carbon in CF4 has no vacant orbital, so no back bonding is feasible. Thus, B−F bond is stronger than CF4. Due to small size and higher electronegativity, carbon has a strong tendency to form multiple bonds either with itself or with the other atoms of similar size such as oxygen and nitrogen. dπ−pπ bonding is the formation of a π molecular orbital by the overlap of a d orbital on one atom with a p or p* orbital on another atom.