Characterization of Synthetic and Naturally Occurring Clays by ²⁷ Al and ²⁹ Si Magic‐Angle Spinning NMR Spectroscopy

Magic‐angle spinning nuclear magnetic resonance (MASNMR) spectroscopy ( 27 Al) detected the coordination of Al in clays containing as little as 0.26% Al 2 O 3 . The 29 Si MASNMR of fluorphlogopite showed three distinct Si chemical environments which suggested short‐range ordering. Synthetic laponite and mica‐montmorillonite showed broad 29 Si resonances indicative of short‐range disorder. A saponite showed four 29 Si resonances. Considerable insight into the short‐range ordering of clays can be gained by 27 Al and 29 Si MASNMR.