Chesta - Software for Creating Chemical Potential Diagrams

Table of Contents

What is a chemical potential diagram?

A chemical potential diagram shows the stability regions of various chemical species using the chemical potentials (partial pressure, activity) of components of a system and/or temperature as co-ordinates. They are widely used in the form of Ellingham diagrams and potential-pH diagrams, as they have the advantage of providing a bird's-eye view of the phase relations and possible reactions in the system under study. For more information on chemical potential diagrams, see also an article by H. Yokokawa (H. Yokokawa, J. Phase. Equilib. 20(3), 258, 1999. DOI:10.1361/105497199770335794 ).

Features of Chesta

What Chesta can do

  • Create chemical potential diagrams for multi-component systems: 2D (with 2 axes) and 3D (with 3 axes) diagrams can be created. Chemical systems with more than 3 components can also be handled. (Cutting and projection features are provided to reduce the dimension of the diagrams.)
  • Customize diagrams: Several types of axes such as activity, energy, electrical potential, and temperature are available. This enables creation of Ellingham diagrams and Pourbaix (Potential-pH, E-pH) diagrams. Also, temperature and the activity of each phase can be changed and applied in the diagrams instantly.
  • Output images (in BMP, JPG, and EMF formats): Vector images (EMF) can be edited in other softwares without degradation.
  • Output coordinates of equilibrium points and activities of chemical species: Chesta can be utilized as a tool for equilibrium calculations.

Features not implemented

  • Thermodynamic database is not included: You have to collect data from the literature and input them to data files.
  • Compositional ranges of substances cannot be considered: All compounds are treated as line compounds. 

System requirements

Microsoft Windows 7 or later (64 bit)

Downloads

Chesta 3.4.3 (Latest version)

Chesta 3.4.3.2.zip (Released on Jun. 9, 2023.)

An Excel macro for creating data files is included.

Chesta 2.22 (Discontinued)

Chesta 2.22.zip (Built on Jun. 15, 2008. Released on June 21, 2010.)

Feature comparison

 Chesta 2.22Chesta 3.4.3
LanguagesJapaneseEnglish / Japanese
2D diagramsxx
3D diagramsxx
3D diagrams with a projection axis-x
Cutting diagrams by fixing an axis valuexx
Cutting diagrams with an arbitrary plane-x
Activity axisxx
Electric potential axis (Unit: V)xx
Energy axis (Unit: kJ, eV)-x
Temperature axis (Unit: K, 1/K)-x
Composition - Gibbs energy diagramsx-
Visual settings for individual chemical species-x
Batch saving of imagesx-
Rotation of diagrams by dragging-x
Equilibrium point listxx
Activity list at equilibrium points-x

Screenshots

Examples

Predominance diagrams of the Fe-O2-Cl2 system

Chemical potential diagrams for neutral chemical species with chemical potential and temeprature axes. Units used: bar, kJ, K.

Fe-O2-Cl2 system (1000K)
log pO2 - T diagram
RTln pO2 - T diagram (Ellingham diagram)
log pCl2 - T diagram
RTln pCl2 - T diagram (Ellingham diagram)
log pO2 - log pCl2 - T diagram
log pO2 - log pCl2 - T diagram (Fe-Cl species are made transparent)

Pourbaix (Potential-pH, E-pH) diagrams of the Ag-Cl-H2O system

Chemical potential diagrams for aqueous systems containing ionic species. (Data file) 

Potential-pH diagram of the Ag-H2O system at 298K. The activities of the dissolved species containing silver are 10^-5. The electrochemical window of water is not considered.
Potential-pH diagram of the Ag-H2O system at 298K. The activities of the dissolved species containing silver are 10^-5. Now the electrochemical window of water is considered.
Potential-pH-(log aCl-) diagram of the Ag-Cl-H2O system at 298K. The activities of the dissolved species containing silver are 10^-5.
Cutting the potential-pH-(log aCl-) diagram of the Ag-Cl-H2O system at 298K. The activities of the dissolved species containing silver are 10^-5.
Rotating the potential-pH-(log aCl-) diagram of the Ag-Cl-H2O system at 298K. The activities of the dissolved species containing silver are 10^-5.
Potential-pH-(log aCl-) diagram of the Ag-Cl-H2O system at 298K. The activities of the dissolved species containing silver are varied from 10^-10 to 1.

Author

Naoyuki Hatada, Ph.D.

License

You can use Chesta free of charge for both commercial and non-commercial porposes. Please refer to the license document accompanying Chesta for detailed terms and conditions.

Cite Chesta

Naoyuki Hatada, Chesta - Software for Creating Chemical Potential Diagrams, https://n-hatada.github.io/chesta, accessed Month Date, Year.

History

  • June 21, 2010: Chesta 2.22 released.
  • April 7, 2014: Chesta 3.2.6.9 released.
  • June 3, 2014: Examples updated.
  • August 9, 2022: Website moved; Chesta 3.4.1.15 released. The activities of all chemical species at equilibrium points can now be displayed.
  • August 18, 2022: Chesta 3.4.1.16 released.
  • August 22, 2022: Chesta 3.4.2.0 released. A bug (error occurs when 0 K data are entered) has been fixed.
  • September 14, 2022: Chesta 3.4.2.1 released. Data files that contain whitespace characters before or after strings or numbers can now be correctly interpreted, ignoring the whitespace characters.
  • May 15, 2023: Chesta 3.4.3.0 released. A bug related to the drawing of frames of stability areas has been fixed.
  • June 9, 2023: Chesta 3.4.3.2 released. Minor bugs related to translation have been fixed.

 

This article was updated on June 26, 2024