ChemInform Abstract: The Polar Mixed‐Valent Lanthanum Iron(II,III) Sulfide La₃Fe_2‐δS₇: Synthesis, Crystal and Electronic Structure, ⁵⁷Fe Moessbauer Spectra, Magnetic Susceptibility and Electrical Resistivity.

Abstract

Iron I 7100The Polar Mixed-Valent Lanthanum Iron(II,III) Sulfide La3Fe2-δS7: Synthesis, Crystal and Electronic Structure, 57 Fe Moessbauer Spectra, Magnetic Susceptibility and Electrical Resistivity. -La3Fe1.958S7 is synthesized from the elements in a LiCl/KCl flux (970 K, 14 d). The compound crystallizes in the hexagonal space group P63 with Z = 2 (Ce6Al10/3S14-type structure; single crystal XRD). The structure contains one-dimensional rods of face-sharing FeS6 octahedra and FeS4 tetrahedra. The Fe-centered polyhedra are linked by La atoms, which are coordinated by [7+1] S atoms in a bicapped trigonal prismatic arrangement. The compound shows an antiferromagnetic transition at about 155 K. The electronic band structure suggests pseudo-one-dimensional metallic conductivity. However, due to the defects on the Fe II positions, La3Fe1.958S7 exhibits an activated conduction behavior. -(MILLS, A. M.; BRAEUNLING, D.; ROSNER, H.; SCHNELLE, W.; SEBASTIAN, C. P.; POETTGEN, R.; RUCK*, M.; J. Solid State Chem. 182 (2009) 5, 1136-1141; Inst.