An ORCHESTRA “reaction” object is used to form new entities from existing entities.
In the next example we assume that H+ and CO3-2 are defined earlier in the file.
@species( HCO3-, -1)
@reaction(HCO3-, 3.455, 1, H+, 1, CO3-2)
Alternatively you can use the log K version of the reaction:
@logKreaction(HCO3-, 3.7, 1, H+, 1, CO3-2) You can even mix reactions and logKreactions in a single input file.