Aluminium-27 nuclear magnetic resonance studies of sulphato-complexes of the hexa-aquo aluminium ion

Abstract

A sulphato-aluminium complex and a small amount of dimeric aluminium cation have been detected in aqueous aluminium sulphate solutions by means of ²⁷Al n.m.r. spectroscopy. The sulphato-complex is probably formed from the SO₄ ^2– rather than the HSO₄ ^– ion. The results emphasise the complexity of aluminium sulphate solutions and may throw light upon the old controversy over the exact proportion of water present in aluminium sulphate crystals.