Crystal and electronic structures of two new iron selenides Ba4 Fe3 Se10 and BaFe2 Se4
Résumé
The new ternary selenides, Ba4 Fe3 Se10 and BaFe2 Se4, were synthesized from a reaction of appropriate amounts of elements at high temperature in a silica sealed tube, and their structures were resolved using X-ray single crystal diffraction. BaFe2 Se4 crystallizes in the tetragonal space group I4/m with a=8.008(9) Å and c=5.483(3) Å as cell parameters. It is a new compound with a structure isotypical to the sulfide BaFe2 S4 which belongs to the infinitely adaptive structures series Ba1+x Fe2 S4 . The second compound, Ba4 Fe3 Se10 , crystallizes in the monoclinic space group P21 /n with a=8.8593(1) Å, b=8.8073(1) Å, c=12.2724(1) Å and β=109.037(6)° as cell parameters. It exhibits an original structure with a new type of iron selenide polyhedra. These data were consistent with the powder X-ray diffraction and TEM analyses. Their electronic structures point towards metallicity and electronic correlations for both selenides.2015 Published by Elsevier Inc.