Preparation, crystal structure and physical properties of ternary compounds ( R3N)In, R=rare-earth metal

Abstract

The compounds ( R 3N)In ( R=Sc, La–Nd, Sm, Gd–Tm, Lu) were synthesized by arc melting and sintering reactions from the binaries RN and R 2In. Combined Rietveld refinements on X-ray and neutron powder diffraction data on the Ce-phase and X-ray diffraction for the other phases reveal the compounds ( R 3N)In to crystallize in the perovskite structure ((Ce 3N)In: Pm 3 ̄ m , a=504.89(2) pm; Rietveld: neutron powder diffraction: R F=0.056, R Bragg=0.104, X-ray powder diffraction: R F=0.069, R Bragg=0.115; refined composition Ce 3InN 0.92(1), chemical analysis Ce 3InN 0.91(2)O 0.05(1)). Compounds R 3In (AuCu 3 structure type) are known for R=La–Sm. Nitrogen is able to stabilize this AuCu 3-substructure with R=Gd–Tm, Lu and Sc. In measurements of the magnetic susceptibility (Ce, Pr, Nd, Sm, Tb: antiferromagnetic ordering at low temperature) and X-ray absorption spectroscopy at the R- L III-edges the rare-earth atoms behave like R 3+ species in insulating compounds. The electrical resistivity of the Sc, Ce and Nd compounds shows metallic temperature dependence. Chemical bonding was analyzed via LDA-COHP calculations for (La 3N)In showing ionic polyhedra NLa 6/2 embedded in a metallic matrix.