Materials Data on BaTlCuO4 by Materials Project

Abstract

BaCuTlO4 crystallizes in the tetragonal I4/mmm space group. The structure is two-dimensional and consists of two BaCuTlO4 sheets oriented in the (0, 0, 1) direction. Ba2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Ba–O bond distances ranging from 2.69–3.31 Å. Cu3+ is bonded in a square co-planar geometry to four equivalent O2- atoms. All Cu–O bond lengths are 1.91 Å. Tl3+ is bonded to six O2- atoms to form a mixture of distorted edge and corner-sharing TlO6 octahedra. The corner-sharing octahedral tilt angles are 13°. There are a spread of Tl–O bond distances ranging from 2.02–2.66 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a 5-coordinate geometry to one Ba2+ and five equivalent Tl3+ atoms. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ba2+ and two equivalent Cu3+ atoms. In the third O2- site, O2- is bonded in a 1-coordinate geometry to four equivalent Ba2+ and one Tl3+ atom.