There is a clear separation between E min distributions for QM9 molecules that are reported and unreported as shown in fig. . E min values for unreported molecules are on average higher than those for reported molecules, where the median E min for unreported molecules is 59 kcal/mol and only 8% of reported molecules exceed 59 kcal/mol. Above 26 kcal/mol, a molecule becomes more likely to be unreported (i.e. unsynthesizable) than reported (i.e. synthesizable) with the probability of being reported quickly dropping with increasing E min . There is a noticeable peak in the E min distribution for reported molecules at E min = 0, whereas the same is not seen for unreported molecules; the probability of a molecule being reported is maximized at E min = 0, where 84% of molecules here are reported. There are almost no reported molecules with E min above 100 kcal/mol, meaning low E min is necessary for synthesizability. But because there are also unreported molecules with E min as low as 0, E min is a necessary, but not sufficient condition for synthesizability.