Contrary to recent experimental evidence suggesting that the monocyclic ring is the most
stable 20-atom carbon species, highly accurate calculations convincingly predict that the
smallest fullerene, dodecahedral C20, has the lowest energy. A related corannulene-like
bowl is nearly degenerate in energy to the fullerene. Thermodynamic considerations
suggest that at formation temperatures of around 700 K the bowl should be the dominant
species.