We are calculating some redox equilibria - it would be useful to see a plot of activities vs. T to decide on what gases to use. A user-friendly thermo program that isn't too expensive would help a lot. Suggestions welcomed.
HSC Chemistry would not help, if you do not know the activity coefficients functional dependence (must be entered manually in GIbbs module INI file). Same concerns all others, unless soluitons in question are already in the databases. For example FactSAGE provides an option to use real or ideal gas phase (in the first option, you may see fugacities of the gas components after running Equilib mode and plotting the results. For ideal phase activities are naturally equivalent to concentrations).
So maybe the question is which database you need to consist compounds of interest?
If you already have such database (and even in a correct format), you may try MatCalc (like Thermocalc but almost free). If you have equations for parameters, you may try to create a proper database (depending on the software you are going to use).
I am using FactSage, which does not only do the Gibbs energy minimization, but comes also along with a good choice of databases (thousands of substances + many mixtures). Other data (if available) can be added by hand. Optimization of Gibbs free energy (for substances + excess data for mixtures) is possible too.
i saw that SUPCRT92 has been suggested for high temperatures and pressures computations in this conversation. does anybody know if it is suitable for mineral equilibria thermodynamic constants computation in deep sedimentary basins? does anybody know if it is still available for free download? i tried to use the use link suggeted by Stefan but it doesn't work anymore...
FactSage can be very helpful. Go to the web site http://www.factsage.com for more information. It is important to contact the developers with regard to the chemical elements in your system.