Frequent Co-Crystal Formers

The first step in the generation of the database of molecular properties in cocrystals was the retrieval of co-crystal structures from the CSD. Co-crystals were defined as organic structures containing at least two eharge neutral nonsolvent molecules with different structural formulas. To avoid possible statistical bias by the frequent occurrence of some eommonly used eo-formers e.g., urea, 4,4 -bipyridine, see Table 1 in ref. 7), struetures with these moleeules were excluded. Initial survey of the data showed that inelusion eompounds, which consist of a large and a small molecule, form a distinet group in the data set. Co-crystals of molecules with more than 30 and with less than six nonhydrogen atoms were thus removed and the analysis foeused on eo-erystals other than inclusion compounds. The final data set eontained 710 struetures. 

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