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Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations
(BaMgTlSnO4)2Mg(SnO2)2 crystallizes in the tetragonal I4/mmm space group. The structure is two-dimensional and consists of two BaMgTlSnO4 sheets oriented in the (0, 0, 1) direction and two Mg(SnO2)2 sheets oriented in the (0, 0, 1) direction. In each BaMgTlSnO4 sheet, Ba2+ is bonded in a 5-coordinate geometry to five O2- atoms. There are one shorter (2.34 Å) and four longer (3.05 Å) Ba–O bond lengths. Mg2+ is bonded in a distorted see-saw-like geometry to four equivalent O2- atoms. All Mg–O bond lengths are 2.20 Å. Tl1+ is bonded to six O2- atoms to form distorted TlO6 octahedra that share corners with four equivalent TlO6 octahedra, a cornercorner with one SnO5 trigonal bipyramid, and edges with eight equivalent TlO6 octahedra. The corner-sharing octahedral tilt angles are 6°. There are a spread of Tl–O bond distances ranging from 2.34–3.35 Å. Sn3+ is bonded to five O2- atoms to form distorted SnO5 trigonal bipyramids that share a cornercorner with one TlO6 octahedra and corners with four equivalent SnO5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 0°. There are one shorter (2.00 Å) and four longer (2.17 Å) Sn–O bond lengths. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to two equivalent Mg2+ and two equivalent Sn3+ atoms to form a mixture of distorted edge and corner-sharing OMg2Sn2 trigonal pyramids. In the second O2- site, O2- is bonded to one Ba2+ and five equivalent Tl1+ atoms to form a mixture of edge and corner-sharing OBaTl5 octahedra. The corner-sharing octahedral tilt angles are 6°. In the third O2- site, O2- is bonded in a 1-coordinate geometry to four equivalent Ba2+, one Tl1+, and one Sn3+ atom. In each Mg(SnO2)2 sheet, Mg2+ is bonded in a body-centered cubic geometry to eight equivalent O2- atoms. All Mg–O bond lengths are 2.58 Å. Sn3+ is bonded in a rectangular see-saw-like geometry to four equivalent O2- atoms. All Sn–O bond lengths are 2.07 Å. O2- is bonded in a distorted see-saw-like geometry to two equivalent Mg2+ and two equivalent Sn3+ atoms.