Metal hydrolysis and associated equilibrium constants

By clicking on a given element in the table below, you can access a PDF file containing its hydrolysis constants (lg values) at infinite dilution and T = 298 K gathered from the most relevant literature compilations (in green, recommended values). Distribution diagrams of the species formed as a function of pH calculated at two concentrations (1 mM = 1x10^-3 mol L^-1 and 1 μM = 1x10^-6 mol L^-1) are also included. Diagrams assume a limiting case of zero ionic strength (i.e., even neglecting plotted ions) and are only intended to provide a quick overview of the distribution of the elements.

The origin of the table is a compilation prepared by the Working Group “NECTAR for highly hydrolysable (HHC) cations” (WG1) of the EU COST Action 18202, Network for Equilibria and Chemical Thermodynamics Advanced Research. Contributors (in alphabetical order): Clemente Bretti, Elvira Bura Nakić, Montserrat Filella, Josep Galceran, Sofia Gama, Elżbieta Gumienna-Kontecka, Gabriele Lando, Demetrio Milea, Andrejz Mular, Bartosz Orzeł, Michaela Rendošová, Vladimir Sladkov, Kamila Stokowa-Sołtys, Yuliya Toporivska, Zuzana Vargová, Emanuele Zanda, Veronika Zinovyeva. All figures were drawn by Emanuele Zanda. The final EU COST table can be found at the COST action webpage.

In this table, many entries still mirror the COST action table but, progressively, errors from the original compilation are, and will be, corrected and values updated. All information has also been uploaded and is updated on Wikipedia.

Equilibrium diagrams

Equilibrium diagrams can be easily obtained from the hydrolysis constants above at other element concentrations using Spana, a program developed by Ignasi Puigdomènech at KTH, Stockholm. Ready data files are available in the periodic table below.

Procedure:

Download and install the version of Java that corresponds to your operating system. Make sure you have Java installed on your computer.
In the table below, click on the element for which you are getting the diagram. A *.dat file will be downloaded to your computer. If some columns appear truncated, use the slider at the bottom of the table to display the missing columns.
Run Spana. Once in the Spana interface, select File > Data File > Open (make a diagram). Select the *.dat file you have previously downloaded and press Open. A new pre-filled interface will appear.
Check that, in the right pane, the box Write a file with results table is ticked. This will create, when generating the plot, a *.csv file that will allow you to plot a better quality plot with Excel or any other plotting software of your choice. In the same right panel, a slider under the heading Number of calculation steps allows you to adjust the smoothness of the curves by increasing the number of calculated points.
By default, in the left/manual panel, Diagram type is set to Fraction and the pH ranges from 0 to 14. You can select a different pH value range. By clicking on Total concentration [compound name] =, you can change the concentration. Press OK to confirm the change, otherwise no figure can be plotted. You can also change the title of the figure.
When you are ready, press the top/left button which shows a graph and the diagram will be generated.