Materials Data on Ba2Mg3Ti4Tl2O12 by Materials Project

(BaMgTiTlO4)2MgTi2O4 crystallizes in the tetragonal I4/mmm space group. The structure is two-dimensional and consists of two BaMgTiTlO4 sheets oriented in the (0, 0, 1) direction and two MgTi2O4 sheets oriented in the (0, 0, 1) direction. In each BaMgTiTlO4 sheet, Ba2+ is bonded in a 5-coordinate geometry to five O2- atoms. There are one shorter (2.42 Å) and four longer (2.94 Å) Ba–O bond lengths. Mg2+ is bonded in a 4-coordinate geometry to four equivalent O2- atoms. All Mg–O bond lengths are 2.12 Å. Ti3+ is bonded to five O2- atoms to form distorted corner-sharing TiO5 trigonal bipyramids. There is one shorter (1.80 Å) and four longer (2.02 Å) Ti–O bond length. Tl1+ is bonded to five equivalent O2- atoms to form a mixture of distorted edge and corner-sharing TlO5 square pyramids. There are one shorter (2.26 Å) and four longer (2.75 Å) Tl–O bond lengths. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted see-saw-like geometry to two equivalent Mg2+ and two equivalent Ti3+ atoms. 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 3°. In the third O2- site, O2- is bonded in a distorted single-bond geometry to four equivalent Ba2+ and one Ti3+ atom. In each MgTi2O4 sheet, Mg2+ is bonded in a body-centered cubic geometry to eight equivalent O2- atoms. All Mg–O bond lengths are 2.41 Å. Ti3+ is bonded in a rectangular see-saw-like geometry to four equivalent O2- atoms. All Ti–O bond lengths are 1.94 Å. O2- is bonded in a distorted see-saw-like geometry to two equivalent Mg2+ and two equivalent Ti3+ atoms.