Welcome to the new interactive version of IUPAC Compendium of Chemical Terminology, informally known as the "Gold Book". On these pages you will find anew browsable, version of this publication. Start by:

• browsing the alphabetical index (left),
• using one of the many thematic indexes (left),
• using the search in the navigation bar (top).

This edition of the IUPAC Gold Book, a compendium of terms drawn from IUPAC Recommendations and Colour Books, has not been updated in several years. Each term is correct based upon the source cited in its entry. However, the term's definition may have since been superseded or may not reflect current chemical understanding. This site, launched July 2019, is the result of an update to the technical underpinnings of the Gold Book website to reflect advances in web technology. IUPAC Divisions will soon review all entries and update the content as needed. Please send anyquestions to[email protected].