Materials Data on Ba4Fe3(Se3F2)2 by Materials Project

Abstract

Ba4Fe3(Se3F2)2 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a 4-coordinate geometry to one Se2- and four F1- atoms. The Ba–Se bond length is 3.45 Å. There are a spread of Ba–F bond distances ranging from 2.68–2.78 Å. In the second Ba2+ site, Ba2+ is bonded in a 4-coordinate geometry to one Se2- and four F1- atoms. The Ba–Se bond length is 3.44 Å. There are a spread of Ba–F bond distances ranging from 2.68–2.84 Å. There are three inequivalent Fe+2.67+ sites. In the first Fe+2.67+ site, Fe+2.67+ is bonded to four Se2- atoms to form FeSe4 tetrahedra that share corners with two equivalent FeSe6 octahedra, corners with two equivalent FeSe4 tetrahedra, and an edgeedge with one FeSe6 octahedra. The corner-sharing octahedra tilt angles range from 43–59°. There are two shorter (2.39 Å) and two longer (2.48 Å) Fe–Se bond lengths. In the second Fe+2.67+ site, Fe+2.67+ is bonded to six Se2- atoms to form a mixture of edge and corner-sharing FeSe6 octahedra. There are a spread of Fe–Se bond distances ranging from 2.63–2.85 Å. In the third Fe+2.67+ site, Fe+2.67+ is bonded to four Se2- atoms to form FeSe4 tetrahedra that share corners with two equivalent FeSe6 octahedra, corners with two equivalent FeSe4 tetrahedra, and an edgeedge with one FeSe6 octahedra. The corner-sharing octahedra tilt angles range from 42–60°. There are two shorter (2.38 Å) and two longer (2.48 Å) Fe–Se bond lengths. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to two equivalent Ba2+ and three Fe+2.67+ atoms to form distorted SeBa2Fe3 trigonal bipyramids that share corners with eight FBa4 tetrahedra and corners with three equivalent SeBa2Fe3 trigonal bipyramids. In the second Se2- site, Se2- is bonded in a 1-coordinate geometry to two Fe+2.67+ atoms. In the third Se2- site, Se2- is bonded in a 1-coordinate geometry to two Fe+2.67+ atoms. In the fourth Se2- site, Se2- is bonded to two equivalent Ba2+ and three Fe+2.67+ atoms to form distorted SeBa2Fe3 trigonal bipyramids that share corners with eight FBa4 tetrahedra and corners with three equivalent SeBa2Fe3 trigonal bipyramids. There are two inequivalent F1- sites. In the first F1- site, F1- is bonded to four Ba2+ atoms to form FBa4 tetrahedra that share corners with four FBa4 tetrahedra, corners with four SeBa2Fe3 trigonal bipyramids, and edges with four FBa4 tetrahedra. In the second F1- site, F1- is bonded to four Ba2+ atoms to form distorted FBa4 tetrahedra that share corners with four FBa4 tetrahedra, corners with four SeBa2Fe3 trigonal bipyramids, and edges with four FBa4 tetrahedra.