As mentioned above, a total of 230,550 mononuclear TMCs were extracted from the CSD and as many of their available SMILES as possible were made sanitize-able for a total of 213,278. Using the Hückel method, we obtain SMILES for 217,776 of the 230,550 extracted TMCs. Combining these two methods means that we make 227,124 SMILES of CSD TMCs, that can readily be read into RDKit, available. For those complexes where we have a SMILES for both the fixed CSD and Hückel methods we compare the SMILES in Table .