X-ray-absorption fine structure of selected R2Fe17 nitrides

X-ray-absorption fine structure from the rare-earth L3 edges in R2Fe17N3−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 Å from the rare-earth site. The observed enhancement of the nitrogen backscattering from magnetically 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) sites in Sm2Fe17N3−x.