DOI: 10.17188/1278956
title: Materials Data on Eu2GeSe4 by Materials Project

description: Eu2GeSe4 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are four inequivalent Eu2+ sites. In the first Eu2+ site, Eu2+ is bonded to seven Se2- atoms to form distorted EuSe7 pentagonal bipyramids that share corners with eight EuSe7 pentagonal bipyramids, a cornercorner with one GeSe4 tetrahedra, edges with two equivalent EuSe7 pentagonal bipyramids, edges with three GeSe4 tetrahedra, and faces with two equivalent EuSe7 pentagonal bipyramids. There are a spread of Eu–Se bond distances ranging from 3.09–3.30 Å. In the second Eu2+ site, Eu2+ is bonded to seven Se2- atoms to form distorted EuSe7 pentagonal bipyramids that share corners with eight EuSe7 pentagonal bipyramids, corners with three GeSe4 tetrahedra, edges with two equivalent EuSe7 pentagonal bipyramids, edges with two GeSe4 tetrahedra, and faces with two equivalent EuSe7 pentagonal bipyramids. There are a spread of Eu–Se bond distances ranging from 3.10–3.25 Å. In the third Eu2+ site, Eu2+ is bonded to seven Se2- atoms to form distorted EuSe7 pentagonal bipyramids that share corners with eight EuSe7 pentagonal bipyramids, a cornercorner with one GeSe4 tetrahedra, edges with two equivalent EuSe7 pentagonal bipyramids, edges with three GeSe4 tetrahedra, and faces with two equivalent EuSe7 pentagonal bipyramids. There are a spread of Eu–Se bond distances ranging from 3.09–3.24 Å. In the fourth Eu2+ site, Eu2+ is bonded to seven Se2- atoms to form distorted EuSe7 pentagonal bipyramids that share corners with eight EuSe7 pentagonal bipyramids, corners with three GeSe4 tetrahedra, edges with two equivalent EuSe7 pentagonal bipyramids, edges with two GeSe4 tetrahedra, and faces with two equivalent EuSe7 pentagonal bipyramids. There are a spread of Eu–Se bond distances ranging from 3.10–3.25 Å. There are two inequivalent Ge4+ sites. In the first Ge4+ site, Ge4+ is bonded to four Se2- atoms to form GeSe4 tetrahedra that share corners with four EuSe7 pentagonal bipyramids and edges with five EuSe7 pentagonal bipyramids. There are a spread of Ge–Se bond distances ranging from 2.39–2.41 Å. In the second Ge4+ site, Ge4+ is bonded to four Se2- atoms to form GeSe4 tetrahedra that share corners with four EuSe7 pentagonal bipyramids and edges with five EuSe7 pentagonal bipyramids. There are three shorter (2.40 Å) and one longer (2.41 Å) Ge–Se bond lengths. There are eight inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to four Eu2+ and one Ge4+ atom to form a mixture of distorted edge, face, and corner-sharing SeEu4Ge square pyramids. In the second Se2- site, Se2- is bonded in a distorted see-saw-like geometry to three Eu2+ and one Ge4+ atom. In the third Se2- site, Se2- is bonded to four Eu2+ and one Ge4+ atom to form a mixture of distorted edge, face, and corner-sharing SeEu4Ge square pyramids. In the fourth Se2- site, Se2- is bonded in a 4-coordinate geometry to three Eu2+ and one Ge4+ atom. In the fifth Se2- site, Se2- is bonded to four Eu2+ and one Ge4+ atom to form a mixture of distorted edge, face, and corner-sharing SeEu4Ge square pyramids. In the sixth Se2- site, Se2- is bonded in a distorted see-saw-like geometry to three Eu2+ and one Ge4+ atom. In the seventh Se2- site, Se2- is bonded in a 4-coordinate geometry to three Eu2+ and one Ge4+ atom. In the eighth Se2- site, Se2- is bonded to four Eu2+ and one Ge4+ atom to form a mixture of distorted edge, face, and corner-sharing SeEu4Ge square pyramids.