PubChem Contains the chemical structures of small organic molecules and information on their biological activities. It is organized as three linked databases: PubChem Substance, PubChem Compound, and PubChem BioAssay. NIST Chemistry WebBook Use this National Institute of Standards and Technology website to look up thermochemical data (i.e. heat capacity, vapor pressure), heat of reaction data, IR spectra, mass spectra, ion energetics data, and thermophysical property data (i.e. density) for thousands of compounds (mostly organic). Organic Syntheses Searchable, online version of Organic Syntheses series, which details reliable experimental methods for the synthesis of organic compounds. Spectral Database for Organic Compounds SDBS This free database provides spectral data (mass, CNMR, HNMR, IR) for commercial chemical reagants.
Common Organic Solvents: Table of Properties Bordwell pKa Table Provides equilibrium constants for many organic compounds with pKa values from 0-35 in DMSO. Sigma-Aldrich Online version of the Sigma-Aldrich catalogs covering the 85,000 biochemicals and organic chemicals that they supply. Free registration required to access Material Safety Data Sheets and spectra. WebElements Periodic Table Interactive periodic table of the elements; including description, uses and properties.