The Combined Chemical Dictionary, a part of the CHEMnetBASE service, is a structured database of chemical substances. It includes descriptive and numberical data on chemical, physical and biological properties of compounds.

e-EROS offers a database of reactions and reagents and is fully searchable by structure and substructure, reagent, reaction type, experimental conditions etc. and allows sophisticated full text searches.

The online Handbook of Chemistry and Physics provides data such as physical constants, weights and measures, conversion tables, material properties, and much more. A part of the CHEMnetBASE collection.