Preparation and characterization of lanthanum silicon nitride

Lanthanum silicon nitride (LaSi₃N₅) powder has been prepared under the relatively mild conditions of 1400 ° C and 1 atm nitrogen. Chemical, X-ray diffraction, solid state nuclear magnetic resonance spectra and morphological information on this powder is presented. The X-ray diffraction data and previously published information have been used to develop a more complete specification of the unit cell dimensions.²⁹Si magic-angle spinning nuclear magnetic resonance spectra of LaSi₃N₅ show two chemical shifts at –64.5 and –56.5 p.p.m. These shifts reflect two electronically different types of silicon which have been attributed to the effects of quadrupolar¹³⁹La nuclei and their spatial arrangements around silicon atoms.