Materials Data on Ba2SnSe3F2 by Materials Project
Ba2SnSe3F2 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Ba2+ is bonded in a 9-coordinate geometry to one Se2- and four equivalent F1- atoms. The Ba–Se bond length is 3.57 Å. There are three shorter (2.73 Å) and one longer (2.75 Å) Ba–F bond lengths. Sn4+ is bonded to four Se2- atoms to form corner-sharing SnSe4 tetrahedra. There are a spread of Sn–Se bond distances ranging from 2.52–2.63 Å. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 1-coordinate geometry to one Sn4+ atom. In the second Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to two equivalent Ba2+ and two equivalent Sn4+ atoms. F1- is bonded to four equivalent Ba2+ atoms to form a mixture of distorted corner and edge-sharing FBa4 tetrahedra.