IUPAC Solubility Data Series


During the IUPAC 47th General Assembly, which occurred in 2013 in Istanbul, it was proposed that members of the Subcommittee on Solubility and Equilibrium Data (SSED) of the IUPAC Analytical Chemistry Division participate in the 2014 Fall American Chemical Society National Meeting in San Francisco as a venue to celebrate the publication in early 2014 of the 100th volume of the IUPAC-NIST Solubility Data Series. The Solubility Data Series (SDS, http://www.iupac.org/index.php?id=593) has been providing comprehensive compilations and (whenever possible) critical reviews of published data. This has been a major vehicle for helping IUPAC fulfill one of its long-range goals: international standardization of physical constants. The symposium was hosted by the Division of Chemical Information and cosponsored by the Divisions of Analytical Chemistry and History of Chemistry. The presentations were organized so as to highlight the practical importance and present relevance of the work being done inside the SSED framework on solubility data and stability constants.

Mark Salomon, the present editor-in-chief of the IUPAC-NIST Solubility Data Series, made a brief reference to the history of the project that can be traced back to 1972 when A. S. (Stevan) Kertes proposed to the then IUPAC Commission V.6 a project on collecting and evaluating solubility data. Publication began in 1979 with the first volume on the solubility of helium and neon in liquids. Since then 102 volumes have been published. Besides the historical aspects, Salomon also outlined the process of data compilation and evaluation. In the compilation process all the available literature sources of data for a specific solute/solvent system have to be considered, even the very old ones. For example, solubilities published in the 19th century often compare favorably with values measured recently.  Thus, solubilities of NaCl in H2O published in 1885 were found to be comparable to the best modern results. Sometimes such old values constitute the only source of data available. For each published paper Compilation (data) sheets are built providing information on materials, experimental methods and errors. Where sufficient literature data exist, contributors to the SDS provide critical evaluations of the data to determine their merits. Data can be classified as Recommended when agreement between independent authors exists,  Tentative when sufficient literature comparisons cannot be made, but the data appear to be reasonable, or Rejected when qualitative or incorrect. The format of a typical Compilation sheet was presented as well as the general format for critical evaluations.

Allan Harvey, the co-editor-in-chief of the Journal of Physical and Chemical Reference Data (JPCRD, http://scitation.aip.org/content/aip/journal/jpcrd) where the IUPAC-NIST Solubility Data Series has been published since volume 66 in 1998, made the bridge between NIST Standard Reference Data and the Solubility Data Series. The publication of SDS as articles in the JPCRD substituted their earlier publication as monographs by Pergamon Press (volumes 1 to 53) and Oxford University Press (volumes 54 to 65). In their communicaiton, Harvey and D. R. Burgess analyzed the fruitful cooperation between NIST and IUPAC from the perspective of the journal and in the context of NIST’s mission. Efforts are being made to make the data published in the journal more accessible and useful in the future. An effort to make the contents of the pre-1998 volumes available on the Web in a format that will be easily searchable by researchers was described.

Stuart Chalk (University of North Florida) spoke next about the application of the “REST API for the IUPAC Solubility Data Series: a ‘Skunkworks’ project.” The focus of his presentation was to show a way to make the data published by NIST available in a more web-enabled format. Chalk presented an outlined project to scrape data and metadata from pages of the IUPAC Solubility Data Series (http://srdata.nist.gov/solubility/) and make them available via a REST API on the authors website. The data points/datasets will be published at unique REST URLs for referencing. Finally, multiple export options (HTML, XML, JSON, JSON-LD) are available to allow both human and software usage of the data.

Glenn Hefter (Murdoch University, Australia) spoke about the work being done in IUPAC on the critical evaluation of stability (formation) constants of metal-ion complexes with inorganic and organic ligands in aqueous solution. He traced the history of projects in this area back to the 1950s with the creation of IUPAC Commission V.6 on Equilibrium Data. The present SSED of the IUPAC Analytical Chemistry Division was formed in 2000 when V.6 was re-combined with Commission V.8 on Solubility Data. Stability constants are important for modeling chemical speciation in areas as diverse as medicine, engineering, process control, extractive metallurgy, environmental management, and so on. In his talk Hefter provided an overview of the many contributions that have been made by the IUPAC group to the important task of compiling and critically evaluating the plethora of available stability constant and related thermodynamic data, which are widely dispersed across the scientific literature.

Johan Jacquemin (Queen’s University Belfast, UK) and William E. Acree (University of North Texas, USA) spoke about specific aspects related to the IUPAC projects they chair, “Progresses and prospects in the database on ionic liquids solubilities in molecular solvents” and “Models to evaluate experimental solubility data for crystalline nonelectrolyte solutes in organic mono-solvents and solvent mixtures,” respectively.

Clara Magalhães (University of Aveiro, Portugal) and Earle Waghorne (University College Dublin, Ireland) spoke about the need for reliable data that can help in the creation of new paradigms about the present impact of carbon dioxide in global warming, environment remediation technologies, and the effects of solvents on the thermodynamics of electrolyte and non-electrolyte solubilities, respectively.

Clara Magalhães, Symposium Organizer

The following is an overview of the IUPAC Subcommittee on Solubility and Equilibrium Data (SSED), a handout was made available at the CINF Symposium in San Francisco, and also kindly provided to Chemical Information Bulletin by Clara Magalhães, Chairman of the IUPAC SSED.


The IUPAC Subcommittee on Solubility and Equilibrium Data (SSED)

Who are we?

Membership of the SSED is open to all scientists who wish to contribute. The current membership includes contributors from 21 countries spread over 4 continents.


The main roles of the SSED are the comprehensive compilation and critical evaluation of selected thermodynamic data, specifically:

  • solubilities of gases, liquids and solids in liquids and solids, and
  • stability constants for homogeneous reactions.


Topics range from those of pure scientific interest through to those of pressing environmental, medical and technological importance.

Examples of current projects:

  • Solubility of non-steroidal anti-inflammatory drugs in both neat organic solvents and organic  solvent mixtures
  • Mutual solubility of rare earth metal (Sc, Y, Lanthanoides) bromides in molten alkali bromides
  • Database on solubility and liquid-liquid equilibria of binary mixtures of ionic liquids and molecular solvents
  • Critical evaluation of thermodynamic data of sulfate complexes in solution.

If you are interested in joining the existing project or proposing a new one, please contact us. Your expertise will be valued.

How to contribute?

New contributions are made through proposals addressed to the chairman of the SSED (Prof. M.C. Magalhães, mclara@ua.pt). We welcome proposals and suggestions for work on new projects from chemists everywhere.


Franzosini Award

The Solubility Data Commission, now the SSED, established the Franzosini Award to assist promising young contributors to the Solubility Data Project to attend SSED meetings and conferences. Since 1988, when the award was established, through 2014, the prize has been awarded to 20 recipients from 14 countries.


Publication of stability constants (critically evaluated data) currently occurs as papers in the IUPAC Journal Pure and Applied Chemistry (impact factor in 2013 of 3.1).

Most recent publication:

Powell, K. J.; Brown, P. L.; Byrne, R. H.; Gajda, T.; Hefter G.; Leuz, A.-K.; Sjöberg, S.; Wanner H.; Chemical speciation of environmentally significant metals with inorganic ligands. Part 5: The Zn2++ OH-, Cl-, CO32-, SO42- and PO43- systems. IUPAC Technical Report. Pure Appl. Chem., 2013, 85(12), 2249-2311. http://dx.doi.org/10.1351/PAC-REP-13-06-03.

Publication of solubility data (critically evaluated) currently occurs as papers in Journal of Physical and Chemical Reference Data (impact factor in 2013 of 3.2).

Currently 102 volumes (containing over 30 000 pages) have been published, others are in the pipeline. Editor-in-Chief of the Solubility Data Series: Dr. M. Salomon (marksalomon@comcast.net).

Most recent publication:

Acree, W. E. IUPAC-NIST Solubility Data Series. 102. Solubility of Nonsteroidal Anti-inflammatory Drugs (NSAIDs) in Neat Organic Solvents and Organic Solvent Mixtures. J. Phys. Chem. Ref. Data 2014, 43, 023102; http://dx.doi.org/10.1063/1.4869683

Electronic databases in stability constants and ionic liquids have been or are being developed.


  • Chemicals in the Atmosphere: Solubility, Sources and Reactivity; Fogg, P., Sangster, J., Eds.;  John Wiley & Sons: Chichester, U.K., 2003.
  • he Experimental Determination of Solubilities; Hefter, G., Tomkins, R. P. T., Eds.; John Wiley & Sons: Chichester, U.K., 2003.
  • Biomineralization: Medical Aspects of Solubility; Königsberger, E., Königsberger, L., Eds.; John Wiley & Sons: Chichester, U.K., 2006.
  • Developments and Applications in Solubility; Letcher, T. M., Ed.; RSC Publishing: Cambridge, U.K., 2007.
  • Thermodynamics: Solubility and Environmental Issues; Letcher, T. M., Ed.; Elsevier: Amsterdam, 2007.


The SSED organizes the International Symposium on Solubility Phenomena and Related Equilibrium Processes (ISSP), which has been held every two years for over 30 years. The next symposium is planned for 2016, in Switzerland.

Additional information

For more information consult the IUPAC web page: http://www.iupac.org/nc/home/about/members-and-committees/divisions.html, and choose “Analytical Chemistry Division” and then “Subcommittee on Solubility and Equilibrium Data,” or contact Chairman Prof. M.C. Magalhães (mclara@ua.pt), or Secretary Prof. E. Waghorne (earle.waghorne@ucd.ie).