Two-Dimensional Arrays in the Analysis of Trends in Series of Molecules: Strongly Subspectral Molecular Graphs, Formula Periodic Tables, and Number of Resonance Structures

Two-dimensional arrays consisting of strongly subspectral molecular graphs and formula periodic tables for polycyclic aromatic hydrocarbons are briefly reviewed. New two-dimensional arrays for free-radical benzenoid hydrocarbons are presented with general analytical expressions for counting their number of resonance structures (SC). The structural origin of the coefficients to these analytical expressions is discussed.