Materials Data on Nb3Fe(Se4S)2 by Materials Project

Abstract

Nb3Fe(Se4S)2 crystallizes in the monoclinic Pm space group. The structure is two-dimensional and consists of one Nb3Fe(Se4S)2 sheet oriented in the (1, 0, 0) direction. there are three inequivalent Nb4+ sites. In the first Nb4+ site, Nb4+ is bonded in a 8-coordinate geometry to eight Se+1.25- atoms. There are a spread of Nb–Se bond distances ranging from 2.64–2.76 Å. In the second Nb4+ site, Nb4+ is bonded in a 8-coordinate geometry to eight Se+1.25- atoms. There are a spread of Nb–Se bond distances ranging from 2.65–2.82 Å. In the third Nb4+ site, Nb4+ is bonded to three Se+1.25- and three S2- atoms to form distorted NbSe3S3 octahedra that share edges with two equivalent NbSe3S3 octahedra and edges with two equivalent FeSe3S3 octahedra. There are two shorter (2.69 Å) and one longer (2.83 Å) Nb–Se bond lengths. There are one shorter (2.30 Å) and two longer (2.43 Å) Nb–S bond lengths. Fe2+ is bonded to three Se+1.25- and three S2- atoms to form FeSe3S3 octahedra that share edges with two equivalent NbSe3S3 octahedra and edges with two equivalent FeSe3S3 octahedra. All Fe–Se bond lengths are 2.47 Å. There are one shorter (2.27 Å) and two longer (2.32 Å) Fe–S bond lengths. There are eight inequivalent Se+1.25- sites. In the first Se+1.25- site, Se+1.25- is bonded in a 2-coordinate geometry to two equivalent Nb4+ atoms. In the second Se+1.25- site, Se+1.25- is bonded in a 2-coordinate geometry to two equivalent Nb4+ atoms. In the third Se+1.25- site, Se+1.25- is bonded in a 4-coordinate geometry to three Nb4+ and one Fe2+ atom. In the fourth Se+1.25- site, Se+1.25- is bonded to four Nb4+ atoms to form distorted corner-sharing SeNb4 tetrahedra. In the fifth Se+1.25- site, Se+1.25- is bonded in a 2-coordinate geometry to two equivalent Nb4+ atoms. In the sixth Se+1.25- site, Se+1.25- is bonded in a 2-coordinate geometry to two equivalent Nb4+ atoms. In the seventh Se+1.25- site, Se+1.25- is bonded in a 3-coordinate geometry to one Nb4+ and two equivalent Fe2+ atoms. In the eighth Se+1.25- site, Se+1.25- is bonded in a 3-coordinate geometry to three Nb4+ atoms. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded in a 3-coordinate geometry to one Nb4+ and two equivalent Fe2+ atoms. In the second S2- site, S2- is bonded in a 3-coordinate geometry to two equivalent Nb4+ and one Fe2+ atom.