Aqueous Electrolyte Solutions


Inorganic electrolytes such as sea salt and ammonium sulphate are important water-soluble components of atmospheric aerosols. The thermodynamic models of Clegg, Brimblecombe, Wexler and co-workers are based upon available data for aqueous solutions of inorganic acids and salts, and their mixtures. On these pages we tabulate data for for pure aqueous (single solute) solutions.

The data have been compiled with support from ACCENT, the European Network of Excellence for Atmospheric Composition Change (an EC 6th Framework Programme), which is gratefully acknowledged.

Presentation of Data

There are summary pages for each electrolyte, see below, which contain links to the data tables. For aqueous sulphuric acid, for example, there are 6 sets of tables: for osmotic coefficients, EMF measurements, enthalpies, heat capacities, solubilities, and degrees of dissociation of the HSO4 ion.

Compositions of the aqueous solutions are specified in a variety of units in the original publications describing the experiments. Here compositions are given, in most instances, in both the original units and in mol per kg of water (molality). More digits have generally been retained in the tabulated data values than are significant, where these have been converted from the original units or are thermodynamic quantities calculated from the published measurement. This avoids rounding errors, and ensures that the original data values can be recovered if needed. However, it also means that the number of digits should not be taken as an indication of the accuracy or precision of the measurement.

Different types of measurement, though yielding the same fitted quantity, can differ greatly in their accuracy and precision. For example, both isopiestic measurements and electrodynamic balance experiments can be used to obtain osmotic coefficients of solutions, but the former experiment is more accurate by a very large margin. Care should therefore be taken when using the information presented in these pages, and the original publications should be consulted for discussions of the data.

The Systems

The aqueous electrolytes for which data have been compiled are listed below. Click on the names to go to the data pages.

Sulphuric acid

Ammonium sulphate

Ammonium nitrate