John C. Ayers

Thank you Jia, swapping in Zr(OH)5- for Zr(OH)2++ in the basis pane of Act2 as you suggested worked.

I just tried switching to the original thermos dataset thermo.com.V8.R6+.tdat in the Act2 script and I get the expected output:

Here are the files that were supposed to be attached. The zircon_dissolution React output shows that when baddeleyite is saturated log activity of Zr(OH)2++ is -21.6 but the Act2 output shows log activity Zr(OH)2++ at baddeleyite saturation is -12.1. Maybe it's coincidence, but in the React output the basis shows that log10 molalities of Zr(OH)2++ and Zr(total) = -12.1. The activity coefficients of all but the most highly charged species are ~1. zircon_solubility_SiO2_v3.ac2 EQ3_6_Zr_JCA.tdat Zircon_dissolution.rea

I want to plot three reaction traces on an Act2 solubility diagram. When the fluid is saturated in plotted phases the reaction traces should plot on the solubility boundaries. However, the reaction traces plot at much lower activities because the React reaction path is plotting the activity of the aqueous species (Zr(OH)2++), while Act2 is plotting the fluid elemental composition (sum of the aqueous Zr species concentrations = molality of Zr). I want Act2 to plot the fluid elemental composition for the reaction trace. Is there a way to do that? I attach the Act2 script and one of the React scripts that generates a reaction trace. I also attach the dataset I used in both (an edited version of the thermo.com.V8.R6+.tdat dataset).