PubChem
PubChem is a database of chemical molecules as well as their activities against biological assays. a system is remains by the National Center for Biotechnology Information NCBI, a factor of the National the treasure of cognition of Medicine, which is component of the United States National Institutes of Health NIH. PubChem can be accessed for free through a web user interface. Millions of compound tables as living as descriptive datasets can be freely downloaded via FTP. PubChem contains office substance descriptions in addition to small molecules with fewer than 100 atoms and 1,000 bonds. More than 80 database vendors contribute to the growing PubChem database.