X-RAY-ABSORPTION FINE-STRUCTURE OF SELECTED R2FE17 NITRIDES

X-ray-absorption fine structure from the rare-earth L3 edges in R2Fe17 N3-x (R=Sm, Pr, or Nd), x-0.2, establishes that these nitrides have 2. 6 +/- 0.6 nitrogen atoms bonded 2.54-2.57 angstrom from the rare-earth site. The observed enhancement of the nitrogen backscattering from ma gnetically oriented powders of SM2Fe17N3-x establishes that between 80 % and 100% of the nitrogen atoms occupy 9(e) sites of the SM2Fe17N3-x. No evidence is found for partial nitrogen occupancy of the 18(g) site s in Sm2Fe17N3-x.