Bond lengths (r, Angstrom) of typical carbon-carbon bonds correlate linearly with bond dissociation energies (BDEs) in the full range of single, double, triple, and highly strained bonds, with BDEs ranging from 16 to 230 kcal mol(-1). The equation is r 1.748-0.002371 (BDE), tested with 41 typical carbon-carbon bonds, ranging in length from 1.20 to 1.71 Angstrom This sets a maximum bond length limit of 1.75 Angstrom for carbon-carbon bonds.