Overview of chemical compound databases

Dana L. Roth, Web-Accessible Chemical Compound Information, Journal of Electronic Resources in Medical Libraries, September 4, 2008. See also this OA self-archived version (free registration required). Abstract:

Web-accessible chemical compound information resources are widely available. In addition to fee-based resources, such as SciFinder Scholar and Beilstein, there is a wide variety of freely accessible resources such as ChemSpider and PubChem. The author provides a general description of various fee-based and free chemical compound resources. The free resources generally offer an acceptable alternative to fee-based resources for quick retrieval. It is assumed that readers will be familiar with The Merck Index, Handbook of Chemistry and Physics, and Knovel Critical Tables.