Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


The NIST Chemistry WebBook is a site on the Internet ( that provides convenient access to a variety of physical and chemical property data on well defined chemical species and reactions. The site is used by scientists, engineers, educators and the general public.


Intended Impact

It is part of NIST's mission to distribute Standard Reference Data to scientists, engineers, educators, and the general public. The NIST Chemistry WebBook is intended to help fulfill NIST's mission by distributing such data over the Internet.


Develop a web site that provides reliable and convenient access to NIST data on chemical systems.


  • Distribute NIST data for chemical systems in manner that is convenient for NIST's customers.

Research Activities and Technical Approach

The NIST Chemistry WebBook was established in 1996 and has grown to encompass a wide variety of thermochemical, ion energetics, physical, solubility, spectroscopic, and chromatographic data. It includes a variety of data from NIST and outside contributors. The site also includes two special features: a set of interactive physical property models developed at the NIST Boulder labs and a group additivity based estimator for gas phase thermodynamic properties. The many contributors to the WebBook are identified in the "credits" section of the web page at

The greatest technical challenge in the development of the WebBook is the integration of databases from multiple sources into a single collection of data. Problems with integrating these data sets are exacerbated problems associated with the identification of chemical species: inconsistent nomenclature, ambiguous or erroneous references to third party registries, and inconsistent conventions for chemical formulas.

Major Accomplishments

  • The NIST Chemistry WebBook receives more than two million page views per month.
  • Updates of the WebBook include new energy level, gas chromatography, ion thermochemistry and mass spectral data.

Standard Reference Database 69: The NIST Chemistry WebBook (

Created February 11, 2009, Updated October 26, 2018