Sources of some erroneous atom environments in PubChem. a Radium (Ra), rubidium (Rb) and yttrium (Y), b Rhenium (Re), c Rhodium (Rh), d Rutherfordium (Rf) and polonium (Po), e Polonium (Po), f Uranium (U), g Vanadium (V) and tungsten (W), h Actinium (Ac). In all cases: i as present in Compound, ii as deposited in Substance, iii as in the original context, except for (E), where it describes a correct way to annotate the ‘polymer’ aspect of the intended structure ‘polyacenapththylene’. Charges and radical annotation (• doublet monoradical, ^^ triplet diradical) in i are a result of the PubChem standardization protocols. Dashed bonds indicate PubChem non-standard bonds.