The bond length $\mathrm{C}-\mathrm{C}$ (single bond as in ethane) is $1.54 \mathrm{~A}$ and $\mathrm{C}=\mathrm{C}$ (double bond as in ethene is $1.33 Å$. The carbon carbon bond length in benzene has been found to be $1.39 Å$ which lies between single and double bond length value.