  Hexagonal chains are a special class of catacondensed benzenoid system and
phenylene chains are a class of polycyclic aromatic compounds. Recently, A
family of Sombor indices was introduced by Gutman in the chemical graph theory.
It had been examined that these indices may be successfully applied on modeling
thermodynamic properties of compounds. In this paper, we study the expected
values of the Sombor indices in random hexagonal chains, phenylene chains, and
consider the Sombor indices of some chemical graphs such as graphene, coronoid
systems and carbon nanocones.
