You are here: Home / About / About


Speciation mode



CHESS is a high-performance speciation model which can be used to evaluate the chemical state of static or semi-dynamic aquatic systems. These tools allow to simulate the speciation of complex, natural or industrial solutions including oxides, minerals, colloids, organics and gases. Cd speciation in presence of hydrous ferric oxide colloids.


JCHESS is a graphical front-end and helps to quickly visualize the predominant species of an element as a function of some variable quantity. The figure at our left shows the speciation of cadmium in presence of colloidal hydrous ferric oxide, as a function of pH. Graphs are created by the user interface JCHESS and can be adapted to fit most specific needs.


Diagram mode



Activity diagram of Pb JCHESS allows to easily construct speciation diagrams, such as Pourbaix- or activity diagrams, solubility diagrams and Mosaic diagrams. Pourbaix diagrams are often used to quickly grab an idea of which species predominates at specific pH and Eh.


More generally, activity-activity diagrams provide an interpretation of a database for one or several species with imposed activities. The picture above shows the expected speciation of 0.1 mmolal of lead (Pb) as a function of pH and Eh, within the domain of H2O stability. the collored areas areas are mineral phases. Such a diagram or much more complex examples are obtained in a few clicks, as illustrated in one of the screenshots.




JCHESS is an easy-to-use and intuitive graphical interface for CHESS, written in Java in order to take advantage of the cross-platform compatibility of this programming language. JCHESS runs on most common (Java-enabled) platforms such as Windows 95/98/2000/NT, Linux and Solaris. Good news for Macintosh users: MacOS X finally includes a Java 2 interpreter, hence CHESS is available for MacOS as well (screenshots).