About the IUPAC Compendium of Chemical Terminology (Gold Book)

The Compendium is popularly referred to as the "Gold Book", in recognition of the contribution of the late Victor Gold, who initiated work on the first edition. It is one of the series of IUPAC "Colour Books" on chemical nomenclature, terminology, symbols and units (see the list of source documents), and collects together terminology definitions from IUPAC recommendations already published in Pure and Applied Chemistry and in the other Colour Books.

Terminology definitions published by IUPAC are drafted by international committees of experts in the appropriate chemistry sub-disciplines, and ratified by IUPAC's Interdivisional Committee on Terminology, Nomenclature and Symbols (ICTNS). In this edition of the Compendium these IUPAC-approved definitions are supplemented with some definitions from ISO and from the International Vocabulary of Basic and General Terms in Metrology; both these sources are recognised by IUPAC as authoritative. The result is a collection of nearly 7000 terms, with authoritative definitions, spanning the whole range of chemistry.

Some minor editorial changes were made to the originally published definitions, to harmonise the presentation and to clarify their applicability, if this is limited to a particular sub-discipline. Verbal definitions of terms from Quantities, Units and Symbols in Physical Chemistry (the IUPAC Green Book, in which definitions are generally given as mathematical expressions) were developed specially for this Compendium by the Physical Chemistry Division of IUPAC. Definitions of a few physicochemical terms not mentioned in the Green Book were added at the same time (referred to here as Physical Chemistry Division, unpublished).

The first reference given at the end of each definition is to the page of Pure Appl. Chem. or other source where the original definition appears; other references given designate other places where compatible definitions of the same term or additional information may be found, in other IUPAC documents. The complete reference citations are given in the appended list of source documents. Highlighted terms within individual definitions link to other entries where additional information is available.

About the Web 2.0 Version of the Gold Book (2019)

Developed through IUPAC Project 2016-046-1-024, the new version of the website was built to using modern technology (dynamic pages from a SQL database), provides content for both humans and machines (via the API), and anticipates Web 3.0 (the semantic web). The project was developed with ongoing maintainence of this important digital IUPAC asset in mind, with code stored on GitHub and the database perpetually backed up in multiple locations. While the content of the entries in the Gold Book is the same as previous editions, the site will continue to evolve as requests from users and new technologies dictate.

Direct questions and comments to Stuart Chalk (Task Group Chair).

About the Advanced XML Version of the Gold Book (2006-2014)

Authors of the electronic XML version

from the Laboratory of Informatics and Chemistry of the Institute of Chemical Technology, Prague.

Graphic design

from ICT Press.


The XML version was created as part of IUPAC project 2002-022-1-024: Standard XML data dictionaries for chemistry and new content and features are added as part of IUPAC project Enhancement of the electronic version of the IUPAC Compendium of Chemical Terminology.

The content is based on the online PDF version of the IUPAC Gold Book that was hosted by the Royal Society of Chemistry and mostly corresponded to the second edition, compiled by Alan D. McNaught and Andrew Wilkinson (Royal Society of Chemistry, Cambridge, UK) and published in print form by Blackwell Science in 1997. In the process of conversion to XML format, many errors and inconsistencies were fixed. The XML version of the Gold Book also contains more than 500 new entries added by Aubrey Jenkins after the publication of the last printed version.

Main improvements from the previous versions


The online version of the Gold Book is considered to be stable and of production quality. We are well aware that no project of the size and complexity of the Gold Book can ever be perfect, however, we are constantly working on improving it. Please don't hesitate to send any comments or suggestions to the maintainer, Stuart Chalk.

Version history

2017-03-27: Release 2.3.3b. This release is a stabilized version of the pages in 2.3.3. No entries have been change, however page updates that have been made include

The next revision will be a completely new version of the Gold Book website, with dynamically generated pages and new features,
see IUPAC Project 2016-046-1-024 for details.

The complete version history of releases and preview releases is available on a separate page.

Related software tools

In the most recent version, the Gold Book is accompanied by a suite of software tools that enable the users to simply add links to the Gold Book to their online materials, especially HTML. These tools are based on tools that are used internally in production of the Gold Book.

The software tools are placed separately on SourceForge which allows for easier collaboration on the software. Please see the above page for full documentation and download options. Any comment and/or improvements to the code are most welcome.

Additional resources

In relation to the software tools described above, we release additional resource files as part of the Gold Book.

The first one is a list of Gold Book terms and their corresponding IDs in XML format. It is available under the name goldbook_terms.xml. This file can be used either by the provided software tools or by users own tools.


All main features were tested and work in the following browsers: Firefox 3.0.8, Internet Explorer 6.0, 7.0 and 8.0, Opera 9.22, Epiphany 2.24.3.

All pages on the IUPAC Gold Book website are valid XHTML 1.0 documents Valid XHTML 1.0!.

Software used in the Gold Book

The structure search (currently unavailable) page used the MarvinSketch applet by ChemAxon for drawing. The applet was provided under the terms of the FreeWeb license (at the time of implementation).

On the server side, the structure search is implemented in a small custom module on top of the OpenBabel library.

The following software was used to convert the PDF sources of IUPAC Gold Book to the HTML form and the authors would therefore like to acknowledge their respective authors:

SVGMath Conversion of MathML to SVG
BKChem Chemical drawing and generation of chemical indexes
Graphviz Link analysis graphics
Cairo Conversion of mathematical SVG to PNG
Batik Conversion of general SVG to PNG
Saxon XSLT processing
Python General programming

Please note that the software listed above is not in any way related to or endorsed by IUPAC.


The authors would like to acknowledge the help of Cheryl Wurzbacher, production editor for Pure and Applied Chemistry, who made the second release possible by very thoroughly going through the whole Gold Book and reporting to us all the mistakes and errors that we made in the first release. We would also like to acknowledge the help of Eva Dibuszova, the head of ICT Press, with typographic and editorial issues.


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