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A brief history and overview of the Solubility Data project*


IUPAC Commission V.8 (the IUPAC Commission on Solubility Data) adopted, at its formation in 1979, the goal of preparing compilations of all experimental determinations of solubility reported in the world's chemical literature and, where possible, evaluating these data critically. This enormous task is approached by considering systems of two or more well-defined components and producing printed volumes of compilations and critical evaluations of chemically-related systems. The methodology used in compilations and critical evaluations has been described in Chemistry International (1), in the Series itself (e.g., A.S. Kertes in the Foreword to Vol. 27/28) and recently in ref. (2). The results of these efforts are published as volumes in the IUPAC Solubility Data Series (the SDS) ref. (3).

The Commission particularly encourages work on systems of widespread chemical interest and of practical concern to chemically-related areas such as the environment, agriculture, human health and global climate change. However, in practice, the Commission must rely on the interests of those highly-qualified contributors who wish to participate. In earlier years an extensive campaign was undertaken to recruit contributors, based on their expertise identified through their scientific publications. The task of compiling data proved to be much larger than expected initially. For example, in the important systems hydrogen in all solvents, sufficient material was found to produce a double volume 5/6. Since publication of that volume in 1981, sufficient newer references have appeared that a third updated volume could be produced. It has also proved difficult, especially in solid-liquid systems, to cover the area in a systematic way, again because, in part, of individual expertise and interests of contributors.

New contributors who have areas of special expertise, especially in the difficult area of complex salt systems, are always welcomed by the Commission. The list of published volumes indicates that more than 50 scientists from more than a dozen countries have participated thus far in the Solubility Data Series as editors of and major contributors to volumes; at least an equal number have also contributed through various compilations and evaluations. Their names are to be found on the title pages of individual volumes [to list of published volumes].

Classification of Systems.

Systems are classified in the first instance as belonging to one of three categories: gases in liquids, liquids in liquids, or solids in liquids. Within these categories, further classification is based on chemical similarities.

1. Gases in liquids. In this case, a strategy for covering the most important gases has been devised, and has been carried out systematically, for the most part. Simple monatomic and homonuclear diatomic gases in water and aqueous solutions are considered first, followed by heteronuclear diatomics and gases of increasingly complex molecular structure. With some classes, such as aliphatic amines, overlap with liquid-liquid systems occurs with propylamine and higher amines. The methods of reporting and evaluating data differ sufficiently for gases in liquids and for solids in liquids that division according to the most frequently encountered state of aggregation has been inevitable. The strategy is evident from the following list. Unless specified to the contrary (as in vols. 21, 42, 45/46, 50), all volumes contain data on gases in all solvents which have been reported in the literature.

1.1 noble gases: vols. 1, 2, 4
1.2 homonuclear diatomic and triatomic gases: vols. 5/6, 7, 10, 12 (part)
1.3 hydrides (groups 13-15 of the periodic table, except carbon): vol. 21
1.4 selected hydrocarbons: vols. 9, 24, 27/28, 57
1.5 amines: vol. 21 (part)
1.6 polyatomic gases containing oxygen: vols. 8, 12 (part), 43, 50, 62
1.7 sulfides, selenides: vol. 32
1.8 halides: vol. 42
1.9 gases in molten salts (special volume): vol. 45/46

2. Liquids in liquids. Here, binary and multicomponent systems are considered in which the components are normally all liquids at room temperature and atmospheric pressure. However, because groups of chemically-related systems are treated together, some systems containing gaseous or solid components are sometimes included as well. The first area of focus has been the solubility of organic liquids in water. Volumes have been organized for classes of organic compounds whose aqueous solubility is particularly relevant for scientific, industrial and environmental reasons, limited only by the areas of expertise of available contributors. While work is continuing on aqueous binary systems involving other classes of organic compounds, a start has been made on non-aqueous binary and ternary systems. For example, vol. 56 concerns binary systems of alcohols with hydrocarbons, and a volume concerning alcohol-hydrocarbon-water systems is in preparation. The binary systems alcohol-water (vol. 15) and alcohol-hydrocarbon provide systematic background material for evaluating the ternary systems. These systems were chosen mainly because of their importance in the manufacture of fuels. So far, 8 volumes on liquids, or 13% of the total, have been published, as follows.

2.1 binary systems containing water
2.1.1 hydrocarbons in water: vols. 37, 38
2.1.2 alcohols in water: vol. 15
2.1.3 esters in water: vols. 48, 49
2.1.4 halogenated aliphatics in water: vol. 60
2.1.5 halogenated aromatics in water: vol. 20
2.2 binary non-aqueous systems
2.2.1 alcohols with hydrocarbons: vol. 56

3. Solids in liquids are divided into several groups: inorganic, organic and metal-organic salts, organic non-electrolytes. All salts (inorganic and organic) are classified according to the type of anion. Non-electrolyte organics are classified by structure. There are special volumes on pharmaceuticals, many of which are salts. Molten salts and alloys comprise a final group.

In a typical complex inorganic system, binary, ternary and higher systems may all be encountered. For binary systems, systematic methods of evaluation have been devised (2). So far, evaluation of ternary systems has been relatively simple either because of the paucity of data or the occurrence of only one solid phase. Volumes in preparation will deal with more complex systems, such as systems containing common salts of the group 1 and 2 metals and ammonium.

3.1 inorganic salts (for specific cations, see list of volumes)
3.1.1 halides: vols. 11, 22, 40 (part), 47, 65
3.1.2 halates: vols. 14, 30, 40, 44
3.1.3 oxyhalides: vol. 40 (part)
3.1.4 perchlorates: vols. 41, 61
3.1.5 oxides, hydroxides: vol. 23, 52
3.1.5 sulfites, selenites, tellurites: vol. 26
3.1.6 nitrates: vol. 13, 55
3.1.7 phosphates: vol. 31
3.1.8 tetraphenylborates: vol. 18
3.1.9 anions containing C, N and S: vol. 3
3.2 antibiotics: vols. 16/17, 34, 35, 36
3.3 molten systems: vols. 25, 33, 51, 64, 65
3.4 organics: vols. 54, 58, 59
3.5 special systems (mercury): vol. 29

In all three main categories, many projects are in progress, so that the above list will continue to grow in completeness and in coverage of important systems. For comments or suggestions on subject matter for future volumes, contact us.


1. A.S. Kertes, "Solubility Data Project." Chem. Int. 8, no. 5 (1986) 25-28.

2. R. Cohen-Adad, J.W. Lorimer, S.L. Phillips and M. Salomon, "A Consistent Approach to Tabulation of Evaluated Solubility Data: Application to the Binary Systems RbCl-H2O and UO2(NO3)2H2O." J. Chem. Info. Comp. Sci. 35 (4) (1995) 675-696.

3. Volumes in the IUPAC Solubility Data Series (SDS) (volume editors, title, date of publication). > See complete list of volumes published in the SDS.


*This history is an edited version of a paper published by John W. Lorimer in Chem. Int. 18, no. 2 (1996) 47-50.


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