The molar volume of a large polymeric cation [Al13O40H48]7+

Abstract

The molar volume has been measured of the tridecameric aluminium cation [Al₁₃O₄₀H₄₈]⁷⁺. The volume obtained is closely similar to that calculated from the crystal structure so that this large cation appears to have negligible electrostriction on the solvent. It is also clear that the ion is large enough for any structural effects owing to the mismatch between ion size and solvent structure to be insignificant. The results show that electrostriction around an ion is short-range in nature.