Aluminium-27 nuclear magnetic resonance investigations of highly alkaline aluminate solutions

Abstract

The high-field ²⁷Al n.m.r spectra are reported of three solutions from which solid materials can be crystallised containing either a dimeric anion with tetrahedrally co-ordinated aluminium or anions with octahedrally co-ordinated aluminium. In two cases the principal ionic species present in solution is [Al(OH)₄]^– and only in the case of a sodium aluminate solution is evidence obtained that significant concentrations of species exist in solution prior to crystallisation which may be related in composition to that of the crystalline products.