Löslichkeitsprodukte von Metalloxyden und ‐Hydroxyden. 2. Mitteilung. Das Löslichkeitsprodukt des Thallium(III)‐oxydes

1 The solubility equilibrium of thallium(III) oxide at 25° has been investigated by determining [Tl 3+ ] and [H + ] in solutions in contact with the solid phase. [Tl 3+ ] and [H + ] have been measured by EMF‐method at the constant ionic strength 3 M . 2 The precipitation reaction attains a steady state after about 200 hours while the dissolving reaction needs only a few hours. 3 The steady state of both reactions can be expressed by the equation\documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm Tl}^{{\rm 3 +}} + 3/2{\rm H}_2 {\rm O = 1/2Tl}_{\rm 2} {\rm O}_3 + 3\,{\rm H}^{\rm +} $$\end{document} with\documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm log K = 2,34 \pm 0,1}{\rm .} $$\end{document} Since in 3 M NaClO 4\documentclass{article}\pagestyle{empty}\begin{document}$$ \begin{array}{l} {\rm log K}_{{\rm H}_{\rm 2} {\rm O}} = \log [{\rm H}^ +] + \log [{\rm OH}^{\rm '}] = - 14,22 \pm 0,02, \\ {\rm log K}_{\rm c} = \log [{\rm Tl}^{3 +}] \times \log [{\rm OH}^{\rm '}]^3 = - 45,0 \pm 0,2. \\ \end{array} $$\end{document} . 4 Biedermann 's measurements of the hydrolysis of Tl 3+ are discussed with respect to the stability of soluble hydrolysis products.