General formulations for some polycyclic hydrocarbons. Di-q-polyhexes

Di-q-polyhexes are polygonal systems consisting of two q-gons each and otherwise only hexagons. General formulations are reported for the CnHs chemical formulae of such systems for q = 4, 5, 6. The case of q = 4 (terphenylenoids) is treated systematically for the first time. Constant-isomer series of CnHs formulae, which have been known to exist for benzenoids (q = 6) and indacenoids (q = 5), are reported here for terphenylenoids.