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Fact Sheet

ChemIDplus is a free, web-based search system that provides access to structure and nomenclature authority files used for the identification of chemical substances cited in National Library of Medicine (NLM) databases, including the TOXNET® system. ChemIDplus also provides structure searching and direct links to many biomedical resources at NLM and on the Internet for chemicals of interest. The database contains over 380,000 chemical records, of which over 289,000 include chemical structures, and is searchable by Name, Synonym, CAS Registry Number, Molecular Formula, Classification Code, Locator Code, Structure, Toxicity, and/or Physical properties.

There are two versions of this database. The ChemIDplus Lite version is available for simplified Name and RN searching without the need for plugins or applets. ChemIDplus Advanced allows various search capabilities beyond the Lite version including chemical structure, toxicity, and physical property searching.

Web Access/Searching

To use ChemIDplus Advanced, you will need a web browser that has a recent version of Java installed. There is a structure drawing and display applet named Marvin from Chemaxon which is available as a default. An alternative method to provide the capabilities needed to accept a structure query is the Chime plug-in which allows you to view the query structures. The structures displayed as answers use standard web browser graphics (.png). A compatible structure drawing package such as ISIS/Draw will allow custom structure queries to be drawn. Marvin also allows this with MarvinSketch. The Locator Codes are hyperlinked at the substance or web site level to biomedical databases at NLM, on the Internet, and to the SuperList compilation of chemical substances of interest to Federal and state regulatory agencies. Ease of navigation from the Locator Display Page to these other Web sites and vice versa is a characteristic feature of ChemIDplus.

For advanced searchers, there are five types of structure queries: Substructure Search, Similarity Search, and Exact Structure Search, Flex Search, and Flexplus Search. ChemIDplus facilitates structure searching by providing two options that eliminate the need to draw the structure queries. One option, Transfer Structure, pastes the retrieved structure from a previous query to the Structure Input Box while the other option, Structure Similarity Search, starts an immediate search for similar structures.

Enhanced structure display is also available in ChemIDplus Advanced. Under Basic Information, the Structure button displays the chemical structure, 3D representations, and structure descriptors. Structure descriptors include InChI™ (International Chemical Identifier) and SMILES™ (Simplified Molecular Input Line Entry System) notations which are downloadable. The Enlarge Structure feature increases the image size of the structure and allows the user to manipulate the display of the atoms and bonds within the chemical structure.

Further Information

For ChemIDplus content, search strategies, and access, contact:

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Last reviewed: 10 March 2008
Last updated: 10 March 2008
First published: 01 January 1994
Metadata| Permanence level: Permanent: Stable Content