O-17 solid-state NMR examination of La2O3 formation

Solid-state O-17 magic-angle spinning (MAS) NMR spectroscopy has been used to study the formation of hexagonal La2O3 from both dehydroxylation of La(OH)(3) and a sol-gel route starting from lanthanum isopropoxide. Both routes proceed via the formation of the oxyhydroxide [LaO(OH)] which is not commonly observed for other simple oxides. O-17 NMR spectroscopy is very sensitive to structural changes even in amorphous samples and the resonances of specific phases are assigned elucidating the chemical shift ranges of the local oxygen coordinations in these materials. The quadrupolar coupling constant for the OLa4 site in La2O3 is determined by the application of satellite transition NMR spectroscopy.