Figure 6.

Correlation between the Kekulé and Clar bond orders and corresponding DFTB bond lengths for all isomers of the C₂₀–C₇₀ fullerenes. The linear fits are $1.5096-0.2016x$ and $1.5708-0.3851x$ for the Clar and Kekulé models, respectively. For clarity, the graph displays data for only 1% of the total number of 2,978,872 bonds (chosen randomly). The fits have been performed on the complete sets.