Fig. 12From: PubChem atom environmentsTop-10 most frequent atom types (r = 0) unique to Substance and Compound, respectively. Atom types are ranked by their incidence in the respective database: a Substance, and b Compound. Incidence provided in absolute numbers due to very low corresponding percentages. Please note that b (i) is aromatic phosphorus and b (vii) is annotated as a monoradical.Back to article page