DOI: 10.17188/1737916
title: Materials Data on K2FeGe3Se8 by Materials Project

description: K2FeGe3Se8 crystallizes in the monoclinic P2_1 space group. The structure is three-dimensional. there are four inequivalent K1+ sites. In the first K1+ site, K1+ is bonded to seven Se2- atoms to form distorted KSe7 pentagonal bipyramids that share corners with two equivalent KSe7 pentagonal bipyramids, corners with two equivalent FeSe4 tetrahedra, corners with six GeSe4 tetrahedra, an edgeedge with one FeSe4 tetrahedra, and edges with two GeSe4 tetrahedra. There are a spread of K–Se bond distances ranging from 3.38–3.93 Å. In the second K1+ site, K1+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of K–Se bond distances ranging from 3.38–4.00 Å. In the third K1+ site, K1+ is bonded in a 7-coordinate geometry to seven Se2- atoms. There are a spread of K–Se bond distances ranging from 3.36–3.97 Å. In the fourth K1+ site, K1+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of K–Se bond distances ranging from 3.48–3.98 Å. There are two inequivalent Fe2+ sites. In the first Fe2+ site, Fe2+ is bonded to four Se2- atoms to form FeSe4 tetrahedra that share corners with two equivalent KSe7 pentagonal bipyramids and corners with four GeSe4 tetrahedra. There are a spread of Fe–Se bond distances ranging from 2.37–2.47 Å. In the second Fe2+ site, Fe2+ is bonded to four Se2- atoms to form FeSe4 tetrahedra that share corners with four GeSe4 tetrahedra and an edgeedge with one KSe7 pentagonal bipyramid. There are a spread of Fe–Se bond distances ranging from 2.37–2.48 Å. There are six inequivalent Ge4+ sites. In the first Ge4+ site, Ge4+ is bonded to four Se2- atoms to form GeSe4 tetrahedra that share a cornercorner with one KSe7 pentagonal bipyramid, a cornercorner with one FeSe4 tetrahedra, a cornercorner with one GeSe4 tetrahedra, and an edgeedge with one GeSe4 tetrahedra. There are a spread of Ge–Se bond distances ranging from 2.34–2.44 Å. In the second Ge4+ site, Ge4+ is bonded to four Se2- atoms to form GeSe4 tetrahedra that share a cornercorner with one KSe7 pentagonal bipyramid, a cornercorner with one FeSe4 tetrahedra, a cornercorner with one GeSe4 tetrahedra, an edgeedge with one KSe7 pentagonal bipyramid, and an edgeedge with one GeSe4 tetrahedra. There are a spread of Ge–Se bond distances ranging from 2.36–2.44 Å. In the third Ge4+ site, Ge4+ is bonded to four Se2- atoms to form GeSe4 tetrahedra that share a cornercorner with one KSe7 pentagonal bipyramid, a cornercorner with one FeSe4 tetrahedra, a cornercorner with one GeSe4 tetrahedra, and an edgeedge with one GeSe4 tetrahedra. There are a spread of Ge–Se bond distances ranging from 2.35–2.44 Å. In the fourth Ge4+ site, Ge4+ is bonded to four Se2- atoms to form GeSe4 tetrahedra that share a cornercorner with one KSe7 pentagonal bipyramid, corners with two equivalent FeSe4 tetrahedra, and corners with two GeSe4 tetrahedra. There are a spread of Ge–Se bond distances ranging from 2.40–2.48 Å. In the fifth Ge4+ site, Ge4+ is bonded to four Se2- atoms to form GeSe4 tetrahedra that share a cornercorner with one KSe7 pentagonal bipyramid, a cornercorner with one FeSe4 tetrahedra, a cornercorner with one GeSe4 tetrahedra, an edgeedge with one KSe7 pentagonal bipyramid, and an edgeedge with one GeSe4 tetrahedra. There are a spread of Ge–Se bond distances ranging from 2.36–2.44 Å. In the sixth Ge4+ site, Ge4+ is bonded to four Se2- atoms to form GeSe4 tetrahedra that share a cornercorner with one KSe7 pentagonal bipyramid, corners with two equivalent FeSe4 tetrahedra, and corners with two GeSe4 tetrahedra. There are a spread of Ge–Se bond distances ranging from 2.40–2.47 Å. There are sixteen inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 2-coordinate geometry to two K1+ and two Ge4+ atoms. In the second Se2- site, Se2- is bonded in a 2-coordinate geometry to three K1+, one Fe2+, and one Ge4+ atom. In the third Se2- site, Se2- is bonded in a 2-coordinate geometry to one K1+ and two Ge4+ atoms. In the fourth Se2- site, Se2- is bonded in a 3-coordinate geometry to one K1+, one Fe2+, and one Ge4+ atom. In the fifth Se2- site, Se2- is bonded in a 4-coordinate geometry to two K1+, one Fe2+, and one Ge4+ atom. In the sixth Se2- site, Se2- is bonded in a 3-coordinate geometry to one K1+, one Fe2+, and one Ge4+ atom. In the seventh Se2- site, Se2- is bonded in a 3-coordinate geometry to one K1+ and two Ge4+ atoms. In the eighth Se2- site, Se2- is bonded in a 2-coordinate geometry to three K1+ and two Ge4+ atoms. In the ninth Se2- site, Se2- is bonded in a 3-coordinate geometry to one K1+ and two Ge4+ atoms. In the tenth Se2- site, Se2- is bonded in a 2-coordinate geometry to two equivalent K1+ and two Ge4+ atoms. In the eleventh Se2- site, Se2- is bonded in a 2-coordinate geometry to three K1+ and two Ge4+ atoms. In the twelfth Se2- site, Se2- is bonded in a 2-coordinate geometry to three K1+ and two Ge4+ atoms. In the thirteenth Se2- site, Se2- is bonded in a 2-coordinate geometry to two K1+, one Fe2+, and one Ge4+ atom. In the fourteenth Se2- site, Se2- is bonded in a 4-coordinate geometry to two K1+, one Fe2+, and one Ge4+ atom. In the fifteenth Se2- site, Se2- is bonded in a 4-coordinate geometry to two K1+, one Fe2+, and one Ge4+ atom. In the sixteenth Se2- site, Se2- is bonded in a 3-coordinate geometry to one K1+, one Fe2+, and one Ge4+ atom.