The CCDC serves the scientific community through the acquisition, evaluation, dissemination and use of the world's output of small molecule crystal structures by compiling the Cambridge Structural Database (CSD) - the world repository of small-molecule crystal structures.
PubChem, released in 2004, provides information on the biological activities of small molecules. PubChem is organized as three linked databases within the NCBI's Entrez information retrieval system. These are PubChem Substance, PubChem Compound, and PubChem BioAssay. PubChem also provides a fast chemical structure similarity search tool.