As expected the largest cohesive energies are found for the CC optimised crystal structure. But the values are not strongly dependent on the geometry. The values from "H-relax" and "relax" should be considered with caution, since in both cases the neighboring molecules are not fully free to adapt (given the frozen cell parameters) which can result in problems for the 2-body treatment. But irrespective of this fact, the CC values are still extremely close to the experimental estimates, exception made for formamide which again presents an outlier. The results in Table are a clear indication that the cohesive energies (at least for these four systems) are not strongly dependent in the geometry chosen, at least to an extent where error cancellation would go as far as masking errors in excess of 5 kJ•mol -1 .