Commission on Physicochemical Symbols, Terminology, and Units


Commission I.1 coordinates IUPAC activities related to defining, formulating, and disseminating good practice on physicochemical symbols, terminology, and units, and ensuring their long-term continuity.

Its main task is editing the book “Quantities, Units, and Symbols in Physical Chemistry”, known as the Green Book of IUPAC. The 3rd edition was published in 2007 and the 4th edition is close to completion. This book provides a compilation of widely used terms and symbols together with brief definitions. A full text-searchable PDF document is freely available (

The Commission initiates, supervises and coordinates translations of the Green Book. French, Japanese, Portuguese, and Italian translations are available; a Chinese and a German translation are planned. The Commission also coordinates the preparation of abridged didactic versions of the Green Book.

Commission I.1 exchanges information related to physicochemical symbols, terminology, and units with other IUPAC bodies and beyond IUPAC, in particular with BIPM and IUPAP, noting the interdisciplinary nature between chemistry and physics. Meetings are arranged on a case-by-case basis when questions arise with textbook writers, journal editors, scientific societies, and researchers in various fields of science and engineering.

The Commission disseminates good practice by interactions with national societies, presentations at international meetings and publications on the World Wide Web. It also coordinates writing educational articles in good practice concerning physicochemical symbols, terminology, and units.

Current Projects

Meeting Minutes

Concise minutes of the 2019 meeting held at the 50th GA in Paris > minutes110-190709-concise (PDF)

Since, the Commission has met virtually several times in 2020-21:
– Commission I.1 and Task Group on Green Book Abridged, 30 Oct 2020 > minutes110-201030c (PDF)
– ibid. 8 March 2021 > minutes110-210308c (PDF)
– ibid. 1 Apr 2021 > minutes110-210401c (PDF)
– Commission I.1, 16 June 2021 > minutes110-210616c (PDF)
– Commission I.1, 17 Sept 2021 > minutes110-210917c (PDF)
– Commission I.1, 22 Oct 2021 > minutes110-211022c (PDF)

In 2022-23:
– Commission I.1, 6 Jan 2022 > minutes110-220106crev (PDF)

Activity Reports

Access the IUPAC Green Book: