Willis B. Hammond

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.