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Fe-CN aqueous complex


Odeta
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Hello, I have a question about logK's of Fe-CN aqueous complexes in the GWB thermo_minteq database.  Different logK for Fe-cyanide aqueous species are reported in Sehmel, 1989, Critical Reports] Reviews, Volume 41,  (new data in Appendix E) which are also cited in a couple of articles by Dzombak and coauthors.  Sehmel, 1989 logKs for the aqueous Fe-CN species are much stronger than what is included in the GWB database. Can you please give me some feedback why these logK have not been adopted by GWB. . I am attaching the 1989 report here and I appreciate your help, 

Best,

-Odeta Qafoku. 

Critical_Reviews_Vol_41_2011.pdf

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Hi Odeta,

I’m including some bibliographic information from the GWB’s thermo_minteq.tdat dataset below:

This dataset is the thermodynamic database from Visual MINTEQ release 2.40, for use with the GWB programs. The dataset has been compiled from files thermo.mdb, analyt.mdb, and comp.mdb.

The Visual MINTEQ database is maintained by Jon Petter Gustafsson, KTH (Royal Institute of Technology), Stockholm, Sweden. The conversion code was written by Daniel Saalfeld and Craig Bethke, University of Illinois, September 2003. This version was compiled in December 2005 by Jon Petter Gustafsson.

It’s not entirely clear to me whether the results of this compilation were merely recommendations or were actually included in an update to Minteq. And as far as I’m aware, Visual Minteq diverged from the original Minteq some time ago. In any case, we are not specialists in thermodynamic data and we don’t change our thermodynamic datasets from release to release, apart from adding support for new features.  

Our datasets are fully editable by our users. You are free to modify any of the equilibrium constants in the datasets, add new reactions, adjust redox coupling, and so on. We built a graphical editor called TEdit for modifying the thermo datasets, but you can alternatively use any text editor. For more information on TEdit, please see Chapter 9 in the GWB Essentials Guide.

Regards,

Brian Farrell
Aqueous Solutions
 

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Great, thank you. I created the new data base using the TEdit. I was curious if there was any other reason that Minteq_thermodata was not updated with the new logK. I appreciate your fast response.

Best,

-Odeta. 

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You're welcome. I'm glad to hear that you were able to use TEdit to make your dataset.

Unfortunately, there is no ultimate dataset that is appropriate for everyone. There will always be tradeoffs between completeness and accuracy. Every user needs to be a judge of what data is appropriate for their specific applications.

Cheers,
Brian

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