Materials Data on Eu3Sn2S7 by Materials Project
Eu3Sn2S7 crystallizes in the orthorhombic Pbam space group. The structure is three-dimensional. there are two inequivalent Eu2+ sites. In the first Eu2+ site, Eu2+ is bonded in a body-centered cubic geometry to eight S2- atoms. There are four shorter (3.15 Å) and four longer (3.18 Å) Eu–S bond lengths. In the second Eu2+ site, Eu2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of Eu–S bond distances ranging from 2.96–3.21 Å. Sn4+ is bonded to five S2- atoms to form corner-sharing SnS5 trigonal bipyramids. There are a spread of Sn–S bond distances ranging from 2.46–2.79 Å. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded in a distorted see-saw-like geometry to two equivalent Eu2+ and two equivalent Sn4+ atoms. In the second S2- site, S2- is bonded to four Eu2+ and one Sn4+ atom to form distorted SEu4Sn square pyramids that share corners with two equivalent SEu4Sn2 octahedra, corners with eight SEu4Sn square pyramids, edges with five SEu4Sn square pyramids, a faceface with one SEu4Sn2 octahedra, and a faceface with one SEu4Sn square pyramid. The corner-sharing octahedral tilt angles are 60°. In the third S2- site, S2- is bonded to four Eu2+ and one Sn4+ atom to form distorted SEu4Sn square pyramids that share corners with three equivalent SEu4Sn2 octahedra, corners with eight SEu4Sn square pyramids, an edgeedge with one SEu4Sn2 octahedra, edges with five SEu4Sn square pyramids, and a faceface with one SEu4Sn square pyramid. The corner-sharing octahedra tilt angles range from 9–34°. In the fourth S2- site, S2- is bonded to four equivalent Eu2+ and two equivalent Sn4+ atoms to form SEu4Sn2 octahedra that share corners with ten SEu4Sn square pyramids, edges with two equivalent SEu4Sn2 octahedra, edges with two equivalent SEu4Sn square pyramids, and faces with two equivalent SEu4Sn square pyramids.