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From: Paul Jensen Subject: Au bisulfide thermodata Is there a dataset for Au bisulfide complexes ready to plug into the thermodataset?

From: Louis Bernier Subject: info Cd I would like to know if there is a reason why cadmium is not part of the basis species in LLNL thermodynamic database? From: Karen E. Wright Subject: Re: info Cd You need to switch databases. The database thermo.com.v8.r6+.dat has data for Cd. Unfortunately you will find that for some of these kinds of metals you will be unable to use features like the Pitzer or h-m-w.

From: Paul Foellbach Subject: Gold hydrosulfides thermo data I am interested in the species AUHS°, Au(HS)2- and Au(CN)2-, this species aren't in the thermo.dat. Where can I find and get these species?

From: Paul Foellbach Subject: Ion size of Cu(HS)2- with Cu+ I attempt to add the Cu+-hydrosulphide species Cu(HS)2- to the thermo.dat-database with the appropriate thermodynamic data. One necessary parameter I can't find in my literature. This is the ion size of this species. Does anyone know a suitable reference or how I can manage this parameter.

From: James Cleverley Subject: SUPCRT to GWB database conversion I am looking for a method of automatically converting supcrt output - set up to give the standard GWB log K grid - into a GWB type input file. All of the information required by GWB is in the supcrt file and I guess the main part of any conversion would be simple text reformatting. Does anyone know of or have a script that they have used to do this?? Why bother with an automated approach?? Well two reasons: 1) This would allow the fast creation of datasets at P-T conditions outside the scope of Psat and 25-300C, and 2) When updating the datasets with new data for species it is not only time consuming to re-enter a large amount data by hand but also there maybe cases where the phase you are updating is used in the reaction of other species or minerals else where. Hence any log K values using that species will differ. If no one knows of anything I can see I will have to dust off my Fortran or C books, but any help with any issue such as this or conversion between EQ3/6 and GWB would be a great help not only to us but also to everyone.

From: James Cleverley Subject: EQ3/6 to GWB database conversion Does anyone know of or have some software for converting EQ36 data files to GWB format. I can see that most of the data is in the correct order and would just take a bit of time to write a re-format script but don't want to re-iterate something that may already be available. We have a series of compilation EQ3/6 datafiles made for different pressure and temperature ranges but more importantly with lots of extra data.

From: Tullis Onstott Subject: Microbial media - Cysteine I've been using GWB to model some of our anaerobic enrichment media and there are a few compounds that are not in the current database that would be helpful. One in particular is Cysteine-HCL which is used to poise the pe by removing residual O2. Does anyone know where one can locate thermochemical data or even the reaction for this compound?

from: Paul Foellbach Subject: Tellurium data? I'm looking for thermodynamic data for the element Tellur, Te. I would be pleased at a tip about a dataset, that contains thermodynamic data of Tellur and where you can download or get it.

From: Steven Cucolo Subject: Thermo Datasets for Solid Solution Minerals Does anyone know of a thermo database for GWB that contains solid solution minerals, specifically those of the plagioclase series (Albite-Anorthite)? None of the datasets I've seen contain them.

From: Greg Anderson Subject: REE data There are quite a few problems with the REE data in thermo.com.v8.r6+.dat. 1. There are many redundant species. Two methods are used to write REE hydrolysis reactions, differing only in the number of H2O. The number of metal ions and H+ are the same, so log K should be the same. However, the two methods come from different references, so there are some (generally small) differences. Using Dy as an example, the two methods are Dy+++ + 4H2O = Dy(OH)4- + 4H+; log K(25C) = 33.4803 Dy+++ + 2H2O = DyO2- + 4H+; log K(25C) = 33.4804 Reactions in the DyO2- form are from Haas, Shock and Sassani (1995) and have data for higher temperatures; data in the Dy(OH)4- form are from Spahiu and Bruno (1995), and are for 25C only. I have no idea as to accuracy, but as there are small differences at 25C, using the Haas et al. data at least gives access to someone's idea of high T behavior. I suggest commenting out the (OH)4- forms. The REE with redundant forms are: log K(25C) ============================================================ Nd Nd(OH)4- and NdO2- 37.0803 and 37.0721 Sm Sm(OH)4- and SmO2- 36.8803 and 35.0197 Eu Eu(OH)2+ and EuO+ 14.8609 and 16.3370 Eu(OH)3(aq) and EuO2H(aq) 24.1253 and 25.4173 Eu(OH)4- and EuO2- 36.5958 and 34.5066 Gd Gd(OH)4- and GeO2- 33.8803 and 34.4333 Dy Dy(OH)4- and DyO2- 33.4803 and 33.4804 Er Er(OH)4- and ErO2- 32.5803 and 32.6008 Yb Yb(OH)4- and YbO2- 32.6803 and 32.6741 ============================================================= 2. Many of the REE have a sign error on the oxidation reaction,resulting in the divalent form being stable at all oxidizing conditions. For example, the reaction Ce++ + H+ + 0.25 O2(aq) = Ce+++ + 0.5 H2O; log K = -83.6754 The log K is actually +83.6754. The log K values are: Element Current logK Correct logK status ======================================================= La -72.4754 72.4754 error Ce -83.6754 83.6754 error Pr -79.9754 79.9754 error Nd -64.3754 64.3754 error Pm -65.2754 65.2754 error Sm 47.9624 47.9624 OK Eu 27.5115 27.5115 OK Gd -84.6754 84.6754 error Tb -78.7754 78.7754 error Dy -61.0754 61.0754 error Ho -67.3754 67.3754 error Er -70.1754 70.1754 error Tm -58.3754 58.3754 error Yb 39.4595 39.4595 OK ======================================================== The ones with the wrong sign are from Spahiu and Bruno (1995), and this is an error in their compilation, not in converting the data to GWB. The ones with the right sign are from Shock and Helgeson (1988), and can be checked using supcrt92. In fact all of them are in supcrt. If you are using REE, it might be a good idea to change all the data to supcrt data, because 1. they then have a certain consistency, and 2. they then all have logKs at high temperatures. If you do this don't forget the O2(g) = O2(aq) swap. I trust no one is fooled by the 4 decimal places. S&B give only one figure past the decimal. If you want to have a copy of Spahiu and Bruno, it is available free from SKB in Sweden. I saw some data there that are not in GWB, but I did not do a thorough comparison. 3. There is a typo in the data for YbPO4(aq). The reaction in thermo.com.v8.r6+.dat is YbPO4(aq) + H+ = HPO4-- + Yb+++; log K = -9.5782 This is a typo. log K should be -0.5782. The reaction in Spahiu and Bruno (1995) p.51 is YbPO4 = Yb+3 + PO4-3; log K = -12.9 Add to this the reaction from the database PO4--- + H+ = HPO4-- log K = 12.3218 and you get -0.5782 for the above reaction. These errors came to light when I translated thermo.com.v8.230 from GWB format to Phreeqc format.

From: Hiroshi Sasamoto Subject: Database Conversion I use the GWB and SUPCRT soft ware to model groundwater chemistry in Japan. Recently, we have revised the SPRONS.dat of SUPCT soft ware using new data published after 1991. I would like to use the revised database based on SPRONS.dat for the calculation using GWB. So if anyone has a conversion program from thermodynamic database of SPRONS to that of GWB, or if anyone can do that, please help me (send me e-mail).

From: Henry Kerfoot Subject: Data for Oleic Acid I need to find data for oleic acid: Aq. solubility, stability constant for Ca complex formation, Ka. Does anyone have such data?

From: Henry Kerfoot Subject: Calcium oxalate I am looking for thermodynamic data on calcium oxalate. I cannot find it. I have been using the LLNL database.

From: Henry Kerfoot Subject: Thermodynamic data request - scapolites Does anyone have any suggestions on where I could find thermodynamic data on the scapolites marialite and on meionite or sodalite or apatite?

From: Henry Kerfoot Subject: stainless steel geochem data I am looking for geochemical data on stainless steel. Is anyone aware of data on stainless steel that I could use?

From: Brugger, Joel Subject: Setchenow coefficients Can I add individual setchenow coefficients for neutral species such as NaCl(aq) and HCl(aq) in a "Debye-Huckel"-formated database?

From: Paul Barton Subject: Unitherm In the recent GCA issue dedicated to Hal Helgeson there is a nice looking treatment of aluminum chemistry by Tagirov and Schott; it would seem to succeed the Pokrovski and Helgeson treatment and is much more comprehensive. Among the references cited by T & S is a data base called "UNITHERM" in a publication titled "HCh: A software package for geochemical equilibrium modeling. A user's guide" by Shavrov and Bastrakov (1999) and issued by the Australian Geological Survey, Department of Industry, Science and Resources. The items perking my interest are data for silicon fluoride species. The reference is strange to me, and it has eluded a cursory exploration of the web. I would like to learn what else the database holds, from whence the data arise, and whether it is proprietary.

From: Michael McCurry Subject: Adding Chabazite to thermo.dat I would appreciate help in modifying the thermodynamic dataset to include Chabazite. The Chabazite data is listed in the SUPCRT data base (below), but has not been previously modified for GWB format (at /users/johnson/gwb). CHABAZITE Ca(Al2Si4)O12*6H2O Cbz Ca(1)Al(2)Si(4)O(18)H(12) ref:1 5.May.78 999999 999999 152.9 247.76 146 44.47 -16.43 1000 From: Craig Bethke Subject: Re: Adding Chabazite to thermo.dat Adding species, minerals, and gases to the GWB dataset is a simple matter. Some points to keep in mind: (1) The dataset format is described in detail in Appendix 3 ("Thermo Datasets", p. 171-176) of the GWB Users' Guide. (2) You do not need to count spaces or align the data fields. (3) Be sure to update the section headers (e.g., "624 minerals") to reflect your changes. (4) Make a backup copy of the original dataset, or better yet copy it to a dataset with a different name ("my_thermo.dat") and work with that file.

From: Paul Barton Subject: thermodynamic data bases There is a substantial level of discontent with the "data base", and (at last) apparent support to do something to improve it. Great! But a word of caution lest we damage the credibility that we all share. The recent flurry identifying specific defects is useful and, of course, needed; but it may mask a larger problem: band aids can improve appearances and functions, but what we really need is a thorough overhaul. In a recent e-mail Dave Wesolowski appropriately described the data base as hanging by a few well defined anchors. That is a good place from which to start, but let us be thoughtful about the way we proceed; that is one reason why Alex's idea of a workshop is appealing. I am reminded of John Haas' examination of the literature on the thermodynamics of the iron oxides maybe 20 years ago. He found that the largest discrepancies among investigations lay not in the measurements themselves, but in the fundamental data used for the calculations, such as those for the H2O decomposition, and the CO-CO2 reaction. We all can find errors, but none of us really knows what the truth is; hopefully, we approach it (probably asymptotically). Every new experimental study may have ripples that infermodification of prior "facts". Therefore, we need a broadly-supported mechanism that continually re-evaluates where we stand and permits steady upgrading of the whole edifice, and the product needs to be transparent so that the chain of assumptions and input data is traceable without major research effort. Today we can only trace back to the next link of what might turn out to be a long and extensively branched chain. Now it is someone else's turn on the soapbox. From: Gregory Miller Subject: RE: thermodynamic data bases Paul Barton's comment that "Today we can only trace back to the next link of what might turn out to be a long and extensively branched chain." May well identify the core issue, and possibly a logical structure to a solution and development of the "FAQ". I envision a database that contains the citations for thermo property sources, and (this is the more difficult part) the sources for the 'lower level' reaction constants used by the citation author. In this manner it may be possible to identify the source of database issues; in some cases problems may have a common root! The database could be annotated by users in an informal manner, and users can access the comments. We could start with the Fe.OH and Ce comments we have. This is an expansion of Andy Wilde's and Mark Logsdon's ideas in that not only can a data base be searched for constants for a compound, but queried for data restricted to certain authors or programs. Practitioners can describe applications and successes and failures of thermo data, other can point to their published work. The need is recognized, there are some approaches in IT that are suited to this, and it seems that the folks at CRC are ready to get started. How should we start? From: Mark J. Logsdon Subject: Re: thermodynamic data bases Seems to me that there are two levels of response needed: 1. GWB-related. The FAQ and archive that may be appropriate for the user-group is not an undertaking at the same level as the much more deep-seated issues of thermodynamics that are being raised. We have some needs in the short term for information among GWB users that can be managed without Craig having to re-answer matters that are already on record somewhere. I had imagined the database questions to be some kind of subset of that, to which users could turn for quick information on database (for this code) issues and leads on how to proceed to the extent that those are known to the user group. 2. "Hard core" Thermo issues. The issues raised by Paul, Greg, Andy, Dave and others are much more fundamental to both "pure" and "applied" geochemistry and extend far outside the GWB users, or even geochemical modeling per se. The resolution of the questions will require major resources of time and effort (i.e., $), and these calls on resources cannot and should not be seen as GWB's responsibility. [Note that the databases in question in our user-group discussions are public-domain products that have been developed by DOE and USGS. Please see discussions in the user's manual about these databases and how and why they are included.] It would be grand - and a goal in the (Robert) Brownian sense of "reach should exceed one's grasp"- to have a "final" database that has some or all of the characteristics described by Greg. Paul's message of today refers to some incipient efforts to jump-start efforts for the basic science and documentation, efforts that, if they are successful, will require support from DOE, NSF and other funding agencies. But those efforts imply a much wider and more time-consuming exercise than the GWB users can mount on their own. From: Dave Decker Subject: Re: thermodynamic data bases The recent discussion about thermodynamic database values has inspired me to write my first post to the GWB group. I have found it interesting (and heartening) that somebody is wondering about the origins of the data posted in thermodynamic databases, and perturbing that the response to this query has not been particularly vigorous. As somebody who has yet to climb very far up on the GWB learning curve, but who has occasionally used the 'other' geochemical models out there, and who has written a little bit of code to deal with arsenic, I would like to throw in my two cents (though I suspect that some of you will question such a high valuation on these comments! ). 1. When assembling a model, one should strive to use thermodynamic values that are consistent with one or two sources, i.e. use values from one research lab - almost guarantees consistent laboratory methodology (if that methodology is appropriate for the modeling problem at hand) from one mineral to the next. Unfortunately, one can't always do this, which leads to comment (2). 2. Clearly, the results of geochemical model simulations (using GWB or other codes) are affected by the range of thermo values in the published literature (i.e. database). More to the point, the outcome of the modeling exercise is dependent upon the modeler's selection of thermo values. Other than comment (1) above, how else are people selecting thermodynamic values for a suite of minerals from a variety of sources that are defensible and consistent? From: Geoffrey Thyne Subject: Re: GWB thermo database questions Dave inspired me to all add my first comment to this group. After a few years of playing with various models, I have found that adjusting the thermo constants to better reflect observations of complex natural systems seems to facilitate using models to represent such systems. And while it is true that changes in thermo data can significantly affect the results for simple systems, usually models of more complex (natural) systems are much less sensitive than you might expect. Finally, as a lab person I can attest that whatever experiment you perform and constants you measure, they do not accurately reflect the natural system. So the question for the group that I would like to hear about is: why shouldn't we modify the lab-derived thermo values (within reason) to make our models more accurately reflect the system we are trying to model? From: D J Wesolowski Subject: Re: GWB thermo database questions I am also inspired for the first time. If you substituted "preconceived notion" for "natural system" in the paragraphs below, then Dr. Thynes suggestion might have some merit. If the model doesn't fit the field observations, it may not be the input thermodynamic data that are at fault, but rather the method attempted to model the more complex natural system. Another way of saying this is that "chaos" is just a mathematician's way of describing a lack of sufficient constraints. From: Ron Schmiermund Subject: Re: GWB thermo database questions I am yet another closet GWB user inspired by the ongoing exchange to make a first posting to the user's group. Each of the recent comments in the thermodynamic data exchange make valid points. There is clearly a lot a of frustration/concern about the very bases of our calculations and a recognition that we can and must do the very best job possible. To that end, I believe that the suggestions of Andy Wilde and Robert Lee should be given much consideration. Goef Thyne raises a good point arguing for the application of appropriate flexibility/judgement in thermodynamic "constants" while Dave Decker argues for intelligent inspection and honoring the best available and most credible and consistent data. Altering values carries with it the burden of justifying those changes each time the adjusted "constants" are used, and being suspected of fudging to obtain preferred results, not to mention potentially causing chaos in the literature. On the other hand, if one were to simply stick by the published values without question there is potential for not recognizing a legitimate data issue and becoming overly confident in a model result because only the best data was used. A transparent data forum might help resolve these issues. The idea of a "universal" database is very appealing and I would like to suggest that it have one additional attribute. Specifically, a linkage from a given mineral or aqueous-species record set to a bulletin board or text file where observations, experience, suggestions or recommended modifications could be posted. From: Mark J. Logsdon Subject: Re: GWB thermo database questions In order to understand Dr. Thyne's suggestion, it seems that one would need to know what the purpose of the modeling under consideration might be. And, then, as with any question, one also would need to understand what counts as an answer. If the ability to measure the "natural system" is better than the ability to measure the thermodynamic behavior of individual minerals, then what's left to model? Or, why would one not use an entirely empirical model rather than invoke any theory at all (for example if one were exercising an initial speciation model)? It seems that the solution proposed by Dr.Thyne would arise only in the instance of an inverse model. But - even putting aside the issue of the thermodynamic data - pretty much everyone agrees that inverse models will be non-unique. Therefore, what would be the advantage of adding subjective degrees of freedom in the thermodynamics. I take this to be related to Dr. Wesolowski's response. For forward modeling, I can see no way in which this could be implemented and lots of pitfalls (of the sort described by Ron Schmiermund) if one were to attempt to do. A forward-modeling exercise (imagine: the HLW program) done with subjectively determined thermodynamic data would never survive a "Daubert" review on at least two grounds (lack of peer review and inability to describe error rates). To be fair, to the extent that the thermodynamic data are not well posed, it is possible that these same objections could be raised with respect to any modeling that used such data. Finally, in the natural sciences it must be the case (except for nearly trivial examples) that a model is a simplification compared to the natural world, whether the model is an experiment or a computation. Surely, that alone (i.e., simplicity) cannot count against using models to explore well-posed questions. From: D J Wesolowski Subject: Re: GWB thermo database questions OK, Here's another go at the issue. I think experimental studies, thermodynamic/kinetic theory and correlation algorithms should be thought of as climber's pitons. Some you can and MUST stake your life on, others can only be considered as tentatively anchored, and clearly some that we think are secure are in fact just about to pull out. The problem in constructing data bases for field applications is that it is difficult to know which ones are reliable. This is a problem that is continuously addressed (examples CODATA, NIST, the MULTEQ program used in the power industry, SUPCRT, etc., etc.) Those close to the experiment or the theory may have a better feel for the reliability of individual anchor points, but they may be so "close to the wall" that they put in too many pitons and never make it to the top. On the other hand, there are many "free climbers" in the game of modeling natural systems who may not even know they've already come off the face and are falling. These folks should think twice about unclipping from their pitons to get to the top faster. This is a problem that is never going to be adequately resolved. In my opinion, at the current time, the semitheoretical, but largely empirical correlation approach being employed by Helgeson, Shock, Sverjensky and co-workers provides the most comprehensive and useful interpolative and extrapolative model for the relevant thermodynamic properties of water/rock interaction systems, and these fellows are very good at evaluating and incorporating the best experimental data and new theoretical developments. However, there remain problems. I offer as an example our recent studies of the first hydrolysis constant of Zn2+ (Benezeth et al. GCA, 1999, v63, pp1571-1586). The constants extracted from the SUPCRT database were found to be orders of magnitude off. In fact, our new results actually improve the positioning of zinc within the correlation framework of this model. So, there is still plenty of room to hammer in more solid anchors, and plenty for the synthesizers to do to keep up with the experiment and theory. Sooner or later the computational folks may put us out of business, but probably not right away. I envy the climbers, and wish them well. Hope they hook on to the right pins! In the meantime, it is very important for all of us to have respect for what each type of geochemist adds to the pot, and we should present a united, enthusiastic and aggressive face to our funders. Confusion and mistrust lead to debacles like Yucca Mountain, which has been under evaluation as a nuclear waste repository for more years than I can even remember. This is a critical societal issue and one that we as geochemists are uniquely equipped to address. I think we need to take a longer view on what is important for individuals to achieve in a given year or even over a lifetime, within the context of why we are doing what we are doing. We should have greater praise for small steps that are solidly placed.

From: Henry Kerfoot Subject: surface datafile error When I try to read the surface data file supplied with the program FeOH+.dat, I get error messages. I fixed one, by adding the 4 characters (aq) immediately following As(OH)3 on line 347. However, I then got this message for line 373 -- Error: unknown reaction entry “B(OH)3� Dataset of surface reactions is corrupt or incomplete! Last line read is line 373: 1.000 (w)FeOH 1.000 B(OH)3 -1.000 H2O I never modified the file until the fix mentioned above... Is it kosher to add (aq) to every entry that is not a part of the species list so that the program will be able to read the surface data file? It does not seems to correspond to the highly intelligent programming I have seen so far in The GWB (Craig? Did you pick up on that blatant flattery?) It seems like there must be something else) I have not thought of (again). Does anyone have experience with this or a suggestion? From: Craig Bethke Subject: Re: surface datafile error The reactions in a surface dataset, of course, must be balanced in terms of species known to the program, i.e., those in the thermo dataset. My guess is that you have selected a thermo dataset other than thermo.dat, the default, with which FeOH+.dat is designed to work. Whoever compiled the dataset you've chosen probably used a slightly different convention for naming species. For example, it appears he or she used the label B(OH)3(aq) instead of B(OH)3. So you should either use the surface dataset as designed, or make a copy and change whatever names are necessary to match the thermo dataset you wish to use.

From: Elias Rosen Subject: Adding basis species I am trying to use GWB to investigate carbon dioxide sequestration via mineral carbonation. In the process under consideration, two organic acids (citrate and edta) are employed to dissolve chrysotile. I have added these species to the thermodynamic data set, using Citrate 3- and EDTA 4- as basis species, and including the various protonations and complexations of these species within the aqueous complexes section of the database. React will read the database, and I can use this altered database to model systems that include edta, but as soon as I specify a concentration for citrate I receive the following error message: React stop: def_basis: add_basis failed -- Hit any key to quit React It appears that both acids have been included using the same formatting, and without knowing what this error refers to I have been unable to resolve this problem.

From: James Laurinat Subject: Problem in adding minerals to thermodynamic data sets I modified the data set thermo.dat by adding data for the mineral sodalite. (The modified data set is called jlau.dat.) When I tried to access the data, I received the following error message: Reading thermodynamic data from: c:program filesgwbgtdatajlau.dat Read data for 646 aqueous species, 624 minerals, and 10 gases. React> swap Sodalite for Al+++ -- Don't know species Sodalite React> From the "Read data" line, I noted that the number of mineral species had not increased from the original number of 624 even though I had incremented this number in my modified data set. Can anyone shed light on what the problem is? Is there a bug in the software? This program will be of little use to me without the ability to add this mineral. From: Geoffrey Thyne Subject: Re: Problem in adding minerals to thermodynamic data sets I believe that you have to alter the line in the database at the start of the minerals section that says 624 to 625 (in this case) to accommodate the addition. From: James Laurinat Re: Problem in adding minerals to thermodynamic data sets I did change the number from 624 to 625, but the printout at the start of the program still said that there were 624 minerals. This led me to suspect that there is a programming error somewhere. If there is an error, it must be located in the portion of the program that looks up mineral species. The program does read in the correct data set. I confirmed this because it reports errors in the constituents of the sodalite mineral. This particular error disappeared when I changed the constituents to include only the basis species. From: James Laurinat Subject: Re: Problem in adding minerals to thermodynamic data sets I have resolved the problem with adding minerals to the thermodynamic data sets. When I added the mineral, I left the equilibrium data blank (the constants were set to a value of 500.0). When I entered fictitious equilibrium data the mineral loaded successfully. As the User's Guide states, species will fail to load if the entered equilibrium data does not span or cannot be extrapolated over the specified temperature range.

From: James Wilson Subject: Supcrt92-GWB database compatibility Could someone please tell me whether the supcrt databases (92/96) are consistent with GWB databases. I have thermodynamic data I wish to incorporate into GWB, and I am using Supcrt92 to generate Log K values. From: James Cleverley Subject: Re: Supcrt92-GWB database compatibility Here at Leeds for supcrt we have: S95.dat (September 1995) Slop98.dat (GEOPIG's 1998 database that includes metal complexes from Sverjensky 1995(?) and loads of organo-metalics) S99.dat (Cl & OH end-member minerals from Berman 1988, Sverjensky, 1991). From what I can see the 1996 GWB database (LLNL) is more comprehensive than our S95 but not as comprehensive as the Slop98! I don't have a 1996 database for supcrt. I know this doesn't help much with your query but does raise the issue of knowing what databases are globally available and a) where they come from, and what they contain. I guess it wouldn't be beyond the realms of possibility to have a GWB/supcrt/EQ36 dedicated web site with compilation lists of what software and databases are available in the public domain?? - just food for thought and to provoke ideas!!!

From: Yoshida Yasushi Subject: header part I have one question for the GWB database. n the header part of the Database, the data of c co2 1, c co2 2, c co2 3, c co2 4, c h2o 1, c h2o2, c h2o3 and c h2o4 are listed. n the GWB users' guide (p.172), c co2 1, c co2 2, c co2 3 and c co2 4 are the data for ' coefficients for calculating the activity coefficients for CO2 and some other electrically neutral species' and 'c h2o 1, c h2o2, c h2o3 and c h2o4' are the data for coefficients for calculation the activity of water', however there is no exact description for these data. would like to know the meaning of these coefficients. * c co2 1 1.224e-1 1.127e-1 9.341e-2 8.018e-2 8.427e-2 9.892e-2 1.371e-1 1.967e-1 * c co2 2 -4.679e-3 -1.049e-2 -3.600e-3 -1.503e-3 -1.184e-2 -1.040e-2 -7.086e-3 -1.809e-2 * c co2 3 -4.114e-4 1.545e-3 9.609e-5 5.009e-4 3.118e-3 1.386e-3 -2.887e-3 -2.497e-3 * c co2 4 0. 0. 0. 0. 0. 0. 0. 0. * c h2o 1 500. 1.45397 500. 1.55510 1.6225 500. 500. 500. * c h2o 2 500. 2.2357e-2 500. 3.6478e-2 4.5891e-2 500. 500. 500. * c h2o 3 500. 9.3804e-3 500. 6.4366e-3 4.5221e-3 500. 500. 500. * c h2o 4 500. -5.362e-4 500. -7.132e-4 -8.312e-4 500. 500. 500. From: Craig Bethke Subject: Re: header part The equations used for these calculations are listed on pages 111-114 of the “Geochemical Reaction Modeling� text. In case you're interested, I've listed at the bottom of this message the actual lines of code used to calculate these parameters. tist = min(Tionst, Timax); sist = min(Sionst, Simax); // Set water activity, using method of Helgeson et al. (1970). rootsi = sqrt(sist); bhat = 1.0 + Bh2o[0]*rootsi; capj = bhat - 2.0*log(bhat) - 1.0/bhat; capd = 2.302590*Adh/(pow(Bh2o[0], 3)*sist); osmot = 1.0 - capd*capj + Bh2o[1]*sist/2.0 + 2.0*Bh2o[2]*sist*sist/3.0 + 3.0*Bh2o[3]*sist*sist*sist/4.0; awlog = -2.0*sist*osmot/(2.30259*55.508682); Bas[H2O]-gamma = pow(10.0, awlog); // Set activity coefficients for certain neutral aqueous species. rootti = sqrt(tist); algco2 = (Cco2[0]+(Cco2[1]+(Cco2[2]+Cco2[3]*tist)*tist)*tist)*tist; aco2 = pow(10.0, algco2);

From: Mark J. Logsdon Subject: Cobaltite Colleagues working on a mining-related problem have asked me to help locate thermo data (with enough pedigree that one can sort out what they mean) for cobaltite. I appreciate (though probably not enough) that there are solid-solution issues in the Fe-Co-As-S system, so any guidance that anyone may have about how all this might be handled would be great. Any leads or suggestions would be most welcome. From: Dave Quirt Subject: Ni-Co-Fe-As-S system, tourmaline, and crandallite This request from Mark Logsdon has reminded me that I also need thermo data in several areas: (1) for the Ni-Co-Fe-As-S system (gersdorffite, rammelsbergite, safflorite, cobaltite, niccolite, etc.), particularly in the 150 to 250 deg C region, (2) for tourmaline-group minerals (specifically dravite), (3) for crandallite-group minerals (specifically goyazite).