Materials Data on Ba2TlNi2O7 by Materials Project
Ba2Ni2TlO7 crystallizes in the tetragonal P4mm space group. The structure is two-dimensional and consists of one Ba2Ni2TlO7 sheet oriented in the (0, 0, 1) direction. 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 2.73–2.89 Å. In the second 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 2.72–2.88 Å. There are two inequivalent Ni+3.50+ sites. In the first Ni+3.50+ site, Ni+3.50+ is bonded in a square co-planar geometry to four equivalent O2- atoms. All Ni–O bond lengths are 1.86 Å. In the second Ni+3.50+ site, Ni+3.50+ is bonded in a square co-planar geometry to four equivalent O2- atoms. All Ni–O bond lengths are 1.87 Å. Tl3+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing TlO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.08 Å) and four longer (2.60 Å) Tl–O bond lengths. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded to two Ba2+ and four equivalent Tl3+ atoms to form a mixture of edge and corner-sharing OBa2Tl4 octahedra. The corner-sharing octahedral tilt angles are 0°. In the second O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ba2+ and two equivalent Ni+3.50+ atoms. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ba2+ and two equivalent Ni+3.50+ atoms. In the fourth O2- site, O2- is bonded in a 5-coordinate geometry to four equivalent Ba2+ and one Tl3+ atom. In the fifth O2- site, O2- is bonded in a 5-coordinate geometry to four equivalent Ba2+ and one Tl3+ atom.