In generating the library of known fragment geometries, we collected 3D structure information from the Crystallography Open Database (COD) , the Platinum Dataset , and Ligand Expo . We stored only fragments with at least 5 atoms that occurred at least 3 times in the superset of these repositories, creating a total of 5,779 fragments. For each fragment the canonical SMILES was stored -ensuring that only unique substructures were retained. When the same fragment was encountered multiple times, only the first conformation found in the database was stored. Future work will focus on including averaged consensus geometries from similar fragment conformers (e.g., chair vs. twist-boat cyclohexane).