Die Selektivität Kristalliner Cer(IV)-Phosphatsulfathydrate gegenüber Li+, Na+, K+, Rb+, Cs+ und NH in absolutem Methanol und absolutem Dimethylsulfoxid

Selectivity of Crystalline Ce^IV Phosphate Sulphate Hydrates for Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺, and NH in Absolute Methanol and Absolute Dimethylsulphoxide The sequence of exchange capacities of Cerium(IV) phosphate sulphate hydrate (CePO₄)₂(HPO₄)_0.74(SO₄)_0.26 · 4,74 H₂O for alkalimetal ions and ammoniumions in absolute methanol at 25°C for the case of a small excess of the exchanger (in relation to the equivalent amount) is given by K⁺ > Rb⁺ ≥ NH₄⁺ > Cs⁺ > Na⁺ > Li⁺. Between the exchange capacity A of these cations and their ionic radii r (given by Ladd) exists the simple relation A = const./r. For Na⁺ the radius of the inner hydration shell must be considered. In absolute dimethyl-sulphoxide under the same conditions the sequence is K⁺ ≥ NH₄ > Rb⁺ > Na⁺ > Cs⁺ > Li⁺. For K⁺, NH₄, Rb⁺ and Cs⁺ the exchange capacity is given by A = const./r + const. · r⁴. The sequences of the alkali ions in both solvents are among the group of 13 sequences which are physicaly significant according to EISENMANNS 's theory. The results are compared with the observations made with water as solvent.