The previous approach was very time-consuming, especially when considering resonance structure generation. A timing comparison of various methods for comparing molecules is shown in Figure for five test cases of comparing identical or different molecules. The first (blue) bar shows timing for resonance structure generation followed by graph isomorphism, and it's clear that the resonance structure generation task increases the total time by over an order-of-magnitude, even for species without resonance. A newly implemented isomorphism method, referred to here as "loose isomorphism," relies on ignoring electron-related features, such as radicals, lone pairs, and bond orders. Multiplicity is considered in order to distinguish electronic states. Charge is not yet considered, since RMG does not currently support ions. The purpose is to have an isomorphism approach which is independent of resonance structures and only focuses on the atom arrangement.