Published in 2003 and updated in 2008, these searchable tables cover physical, solvent, and thermodynamic properties of over 21,000 inorganic and organic compounds and pure substances.

Ready reference book of chemical and physical data, properties, and constants.

Includes constants and property data important to physics and chemistry. Published in 1995.

Tables, constants, and other data from the National Institute of Standards and Technology

Published in 1954, these searchable tables cover a wide range of physical and chemical data and properties including thermodynamics, optics, nuclear physics, etc.

Published between 1924-1930, these searchable tables cover physical, thermodynamic, mechanical, and other important properties of inorganic and organic compounds and pure substances.

ChemSpider is a free database of chemical compound data from across the web, provided for the benefit of the community by the Royal Society of Chemistry (RSC). It aggregates chemical structures and their associated information into a single searchable repository.

PubChem provides information on the biological activities of small molecules including substance information, compound structures, and bioactivity data.

Use the Department of Energy Data Explorer (DDE) to find scientific research data - such as computer simulations, numeric data files, figures and plots, interactive maps, multimedia, and scientific images - generated in the course of DOE-sponsored research in various science disciplines.