Materials Data on Fe2GeSe4 by Materials Project

Fe2GeSe4 is Spinel-like structured and crystallizes in the monoclinic P2_1 space group. The structure is three-dimensional. there are four inequivalent Fe2+ sites. In the first Fe2+ site, Fe2+ is bonded to six Se2- atoms to form FeSe6 octahedra that share corners with eight FeSe6 octahedra, corners with four GeSe4 trigonal pyramids, edges with two FeSe6 octahedra, and an edgeedge with one GeSe4 trigonal pyramid. The corner-sharing octahedra tilt angles range from 49–50°. There are a spread of Fe–Se bond distances ranging from 2.53–2.74 Å. In the second Fe2+ site, Fe2+ is bonded to six Se2- atoms to form FeSe6 octahedra that share corners with eight FeSe6 octahedra, corners with four GeSe4 trigonal pyramids, edges with two FeSe6 octahedra, and an edgeedge with one GeSe4 trigonal pyramid. The corner-sharing octahedra tilt angles range from 49–50°. There are a spread of Fe–Se bond distances ranging from 2.53–2.73 Å. In the third Fe2+ site, Fe2+ is bonded to six Se2- atoms to form FeSe6 octahedra that share corners with four FeSe6 octahedra, corners with two GeSe4 trigonal pyramids, edges with four FeSe6 octahedra, and edges with two GeSe4 trigonal pyramids. The corner-sharing octahedra tilt angles range from 49–50°. There are two shorter (2.38 Å) and four longer (2.49 Å) Fe–Se bond lengths. In the fourth Fe2+ site, Fe2+ is bonded to six Se2- atoms to form FeSe6 octahedra that share corners with four FeSe6 octahedra, corners with two GeSe4 trigonal pyramids, edges with four FeSe6 octahedra, and edges with two GeSe4 trigonal pyramids. The corner-sharing octahedra tilt angles range from 49–50°. There are two shorter (2.38 Å) and four longer (2.49 Å) Fe–Se bond lengths. There are two inequivalent Ge4+ sites. In the first Ge4+ site, Ge4+ is bonded to four Se2- atoms to form GeSe4 trigonal pyramids that share corners with six FeSe6 octahedra and edges with three FeSe6 octahedra. The corner-sharing octahedra tilt angles range from 64–74°. There are three shorter (2.45 Å) and one longer (2.50 Å) Ge–Se bond lengths. In the second Ge4+ site, Ge4+ is bonded to four Se2- atoms to form GeSe4 trigonal pyramids that share corners with six FeSe6 octahedra and edges with three FeSe6 octahedra. The corner-sharing octahedra tilt angles range from 64–74°. There are three shorter (2.45 Å) and one longer (2.50 Å) Ge–Se bond lengths. There are eight inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a rectangular see-saw-like geometry to three Fe2+ and one Ge4+ atom. In the second Se2- site, Se2- is bonded in a rectangular see-saw-like geometry to three Fe2+ and one Ge4+ atom. In the third Se2- site, Se2- is bonded in a rectangular see-saw-like geometry to three Fe2+ and one Ge4+ atom. In the fourth Se2- site, Se2- is bonded in a rectangular see-saw-like geometry to three Fe2+ and one Ge4+ atom. In the fifth Se2- site, Se2- is bonded to three Fe2+ and one Ge4+ atom to form corner-sharing SeFe3Ge tetrahedra. In the sixth Se2- site, Se2- is bonded to three Fe2+ and one Ge4+ atom to form corner-sharing SeFe3Ge tetrahedra. In the seventh Se2- site, Se2- is bonded in a rectangular see-saw-like geometry to three Fe2+ and one Ge4+ atom. In the eighth Se2- site, Se2- is bonded in a rectangular see-saw-like geometry to three Fe2+ and one Ge4+ atom.