Ion Definitions

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Navigation: Models ➔ ( PHREEQC Model Configuration and AQSol Model Configuration ) ➔ Ion Definitions

Latest SysCAD Version: 17 January 2023 - SysCAD 9.3 Build 139.32335


Ion definitions are provided in the IonList.txt file that is located in the Project Configuration (CfgFiles) folder.

  • All ions in the TCE chemistry model MUST have a matching ion in the IonList.txt file. This is a requirement for successful forward and reverse mapping. Unlike species (eg solids) the solver will not start without full mapping of ions.
  • All TCE projects using the cfg file located in the CfgFiles folder will use the same IonList.txt file.
  • In Build 138 if the file is not located in CfgFiles it will use the file located in BaseFiles.

An IonList.txt file is included with SysCAD install and located at c:\SysCADXXX\BaseFiles. If the IonList.txt file is missing from the CfgFiles folder when loading a TCE project requiring Ions, then the file is copied from the supplied BaseFiles folder.

The user can add additional ions to this file in the CfgFiles folder as required for their project. There are two ways to do this:

  1. By pressing the AddUnmappedIonsButton.png on the Config tab page of either the PHREEQC Model Configuration or AQSol_Model_Configuration model.
  2. By manually adding them using a text editor (see explanation of syntax below).

An ion definition provides the name of the ion, followed by its elemental definition. Each element in defined in the definition via the following form:

Element<Valence>Count

An example of a valid ion definition is given below:

HSO4- H<1>1S<6>1O<-2>4-

Note that the specification of valence is optional. Thus, the above definition could also be written as:

HSO4- H1S1O4-