Contains measured binding affinities, primarily for small molecules interacting with proteins considered to be likely drug targets. Also, some host-guest binding data for other supramolecular systems.

Mostly open access source of fundamental and derived data from single crystal X-ray structure determinations from the University of Southampton and EPSRC U.K. National Crystallography Service.

Curated research data on nanomaterials, including physico-chemical characteristics and interactions with biological and environmental systems.

Data measured or compiled and evaluated by the US National Institute of Standards and Technology, both free and for a fee. Includes chemical properties, physical constants, spectroscopic and thermodynamic data, and standard reference data.

Contains molecular properties predicted from quantum mechanics with integrated capabilities for molecular visualization and data sharing.

Database of chemical substances containing descriptive and property information along with bioactivity screening data.

Database of commercially available compounds with 3-D structure representations in a format ready for virtual screening for potential biological activity.