Materials Data on Eu2GeS4 by Materials Project

Eu2GeS4 crystallizes in the monoclinic P2_1 space group. The structure is three-dimensional. there are two inequivalent Eu2+ sites. In the first Eu2+ site, Eu2+ is bonded to seven S2- atoms to form distorted EuS7 pentagonal bipyramids that share corners with eight EuS7 pentagonal bipyramids, a cornercorner with one GeS4 tetrahedra, edges with two equivalent EuS7 pentagonal bipyramids, edges with three equivalent GeS4 tetrahedra, and faces with two equivalent EuS7 pentagonal bipyramids. There are a spread of Eu–S bond distances ranging from 2.96–3.16 Å. In the second Eu2+ site, Eu2+ is bonded to seven S2- atoms to form distorted EuS7 pentagonal bipyramids that share corners with eight EuS7 pentagonal bipyramids, corners with three equivalent GeS4 tetrahedra, edges with two equivalent EuS7 pentagonal bipyramids, edges with two equivalent GeS4 tetrahedra, and faces with two equivalent EuS7 pentagonal bipyramids. There are a spread of Eu–S bond distances ranging from 2.99–3.14 Å. Ge4+ is bonded to four S2- atoms to form GeS4 tetrahedra that share corners with four EuS7 pentagonal bipyramids and edges with five EuS7 pentagonal bipyramids. There are two shorter (2.24 Å) and two longer (2.25 Å) Ge–S bond lengths. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded in a 4-coordinate geometry to three Eu2+ and one Ge4+ atom. In the second S2- site, S2- is bonded in a distorted see-saw-like geometry to three Eu2+ and one Ge4+ atom. In the third S2- site, S2- is bonded to four Eu2+ and one Ge4+ atom to form a mixture of distorted corner, edge, and face-sharing SEu4Ge trigonal bipyramids. In the fourth S2- site, S2- is bonded to four Eu2+ and one Ge4+ atom to form a mixture of distorted corner, edge, and face-sharing SEu4Ge square pyramids.