Materials Data on Ba3Sn2O7 by Materials Project
Ba3Sn2O7 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. there are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Ba–O bond distances ranging from 2.68–3.09 Å. In the second Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with four equivalent BaO12 cuboctahedra, faces with four equivalent BaO12 cuboctahedra, and faces with eight equivalent SnO6 octahedra. There are a spread of Ba–O bond distances ranging from 2.83–3.12 Å. Sn4+ is bonded to six O2- atoms to form SnO6 octahedra that share corners with five equivalent SnO6 octahedra and faces with four equivalent BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 3–7°. There are one shorter (2.08 Å) and five longer (2.10 Å) Sn–O bond lengths. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to four equivalent Ba2+ and two equivalent Sn4+ atoms. In the second O2- site, O2- is bonded to four Ba2+ and two equivalent Sn4+ atoms to form a mixture of distorted corner, edge, and face-sharing OBa4Sn2 octahedra. The corner-sharing octahedral tilt angles are 62°. In the third O2- site, O2- is bonded in a 6-coordinate geometry to four Ba2+ and two equivalent Sn4+ atoms. In the fourth O2- site, O2- is bonded in a 6-coordinate geometry to five equivalent Ba2+ and one Sn4+ atom.