(a) For ptotrs equal to 1 and to 3, compare the bond-length predictions of Eq. (17.57) with experimental carbon-carbon single- and triple-bond lengths.
(b) Look up or use a program to calculate the Hückel bond orders of azulene and compare the predicted bond lengths with the experimental values. [The experimental data can be found in R. J. Buenker and S. D. Peyerimhoff, Chem. Phys. Lett., 3, 37 (1969).]