For the purpose of this publication, MAYGEN was tested with randomly selected molecular formulae. The run times of MAYGEN and OMG are compared in Table , Table and Table . Different from MOLGEN 5.0 , OMG generates structures for additional valences of sulfur (S), phosphorus (P) and nitrogen (N) and therefore more molecules than MOLGEN or MAYGEN . MOLGEN 5.0 uses the default lowest valences for N(3), S(2), and P(3); unless a user defines the higher valences. For all the results given in these tables, MAYGEN generated the same number of structures as MOLGEN 3.5. The numbers reported in the tables are given for Molgen 5.0 since this could be run in batch mode on our Linux servers. Molgen 5.0 has an aromaticity filter that filters out resonance structures of substituted aromatic molecules. This filter is activated by default and therefore Molgen 5.0 generates fewer structures than Molgen 3.5 and MAYGEN. Since bromine (Br) atom type is not defined in OMG it does not generate structures with molecular formulae including Br.