Chemical Thermodynamics and Activity Diagrams

What is it?

An example

After Helgeson, 1970.

Quick Start

Download R from the Comprehensive R Archive Network (CRAN). Start up R, then use these commands to install and load the package and run the examples from the documentation.


Download and Documentation

download Download CHNOSZ, and get other files ( news faq pdf refs )
manual Online manual
examples Output from examples (including figures)
demos Demos (longer examples, with figures)
vignettes Package vignettes ("Regressing thermodynamic data" added in version 1.0.8-2 )

Around the Web

Other Stuff

anim Animations of equilibrium activity diagrams
transfer Reaction path calculations in CHNOSZ
Rpad Interface to CHNOSZ using the Rpad web-based analysis program Not currently available (development stopped); see this development version of Rpad


CHNOSZ is free software licensed under the GPL.

The maintainer of this package is Jeffrey Dick. Please contact me at

Work on this project through 2008 was supported by research grants from the U.S. National Science Foundation and Department of Energy. In 2009-2011, this material is based upon work supported by the National Science Foundation under Grant No. EAR-0847616.

To cite CHNOSZ, use this reference: Dick, 2008. The thermodynamic database represents the work of many different authors. If you publish results of calculations using any of these data, please cite the primary data sources! For a list of references, use the browse.refs() function in the package, or access the table of references here.

Updated 2016-11-01 by Jeffrey M. Dick