Solid‐State NMR Studies of the Structure and Reactivity of Metakaolinite

Abstract
Si atoms in various environments, as well as tetra‐, penta‐, and hexacoordinated AI atoms, have been observed in metakaolinite by high‐resolution solid‐state NMR spectroscopy. Their ratios depend upon the calcination temperature. Studies have shown that the most reactive metakaolinite (calcination temperature 480‐500 °C) is associated with a minimum concentration of hexacoordinate and a maximum concentration of tetra‐ and pentacoordinate Al.