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Keywords:

  • Crystal structure;
  • Iron selenide;
  • Main group elements;
  • Seleno Jamesonite;
  • Semiconductors

Abstract

Single crystals of FePb4Sb6Se14, were obtained from solid-state combination of high purity elemental powders at 873K for three days. Single crystal X-ray structure determination revealed that the compound crystallizes in the monoclinic space group P21/c (no. 14) and adopts the structure of Jamesonite (FePb4Sb6S14). The structure contains two crystallographically independent lead atoms with monocapped and bicapped trigonal prismatic coordinations, three antimony atoms located in a distorted octahedral environment and one iron atom occupying a flattened octahedral coordination. Neighboring monocapped and bicapped trigonal prims around lead atoms share faces and edges to build a corrugated layer parallel to the ac plane. Octahedrally coordinated antimony atoms share edges to form one-dimensional (1D) {SbSe} ribbons connecting adjacent corrugated layers. The distortion of the octahedral coordination around antimony atoms within the {SbSe} ribbons with the longest bond pointing towards the center of the ribbon, suggests the stereochemical activity of antimony lone-pairs with their electron clouds pointing towards the center of the {SbSe} ribbon. The three dimensional framework resulting from the connectivity between the corrugated layers and the {SbSe} ribbons, contains isolated cylindrical voids parallel to [100] which are filled by a 1D FenSe4n+2 straight chain of edge-sharing FeSe6 octahedra. The crystal structure of FePb4Sb6Se14 is closely related to that of FePb3Sb4Se10 as they are formed by similar building units with different sizes.