Materials Data on Ba2Mg3Tl2(WO3)4 by Materials Project
(BaMgWTlO4)2Mg(WO2)2 crystallizes in the tetragonal I4/mmm space group. The structure is two-dimensional and consists of two BaMgWTlO4 sheets oriented in the (0, 0, 1) direction and two Mg(WO2)2 sheets oriented in the (0, 0, 1) direction. In each BaMgWTlO4 sheet, Ba2+ is bonded in a 1-coordinate geometry to five O2- atoms. There are one shorter (2.47 Å) and four longer (2.90 Å) Ba–O bond lengths. Mg2+ is bonded in a 4-coordinate geometry to four equivalent O2- atoms. All Mg–O bond lengths are 2.29 Å. W3+ is bonded to five O2- atoms to form WO5 square pyramids that share a cornercorner with one TlO6 octahedra and corners with four equivalent WO5 square pyramids. The corner-sharing octahedral tilt angles are 0°. There are four shorter (2.00 Å) and one longer (2.05 Å) W–O bond lengths. Tl1+ is bonded to six O2- atoms to form distorted TlO6 octahedra that share corners with four equivalent TlO6 octahedra, a cornercorner with one WO5 square pyramid, and edges with eight equivalent TlO6 octahedra. The corner-sharing octahedral tilt angles are 7°. There are a spread of Tl–O bond distances ranging from 2.38–3.34 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a see-saw-like geometry to two equivalent Mg2+ and two equivalent W3+ 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 7°. In the third O2- site, O2- is bonded in a 1-coordinate geometry to four equivalent Ba2+, one W3+, and one Tl1+ atom. In each Mg(WO2)2 sheet, Mg2+ is bonded in a body-centered cubic geometry to eight equivalent O2- atoms. All Mg–O bond lengths are 2.43 Å. W3+ is bonded in a distorted square co-planar geometry to four equivalent O2- atoms. All W–O bond lengths are 2.07 Å. O2- is bonded to two equivalent Mg2+ and two equivalent W3+ atoms to form a mixture of distorted edge and corner-sharing OMg2W2 tetrahedra.