Materials Data on TiNb6Tl2O18 by Materials Project
TiNb6Tl2O18 crystallizes in the monoclinic C2 space group. The structure is three-dimensional. Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with six NbO6 octahedra. The corner-sharing octahedra tilt angles range from 34–36°. There are a spread of Ti–O bond distances ranging from 1.95–1.97 Å. There are three inequivalent Nb5+ sites. In the first Nb5+ site, Nb5+ is bonded to six O2- atoms to form distorted NbO6 octahedra that share a cornercorner with one TiO6 octahedra, corners with four NbO6 octahedra, and edges with two NbO6 octahedra. The corner-sharing octahedra tilt angles range from 24–50°. There are a spread of Nb–O bond distances ranging from 1.86–2.15 Å. In the second Nb5+ site, Nb5+ is bonded to six O2- atoms to form distorted NbO6 octahedra that share a cornercorner with one TiO6 octahedra, corners with four NbO6 octahedra, and edges with two NbO6 octahedra. The corner-sharing octahedra tilt angles range from 26–49°. There are a spread of Nb–O bond distances ranging from 1.87–2.14 Å. In the third Nb5+ site, Nb5+ is bonded to six O2- atoms to form distorted NbO6 octahedra that share a cornercorner with one TiO6 octahedra, corners with four NbO6 octahedra, and edges with two NbO6 octahedra. The corner-sharing octahedra tilt angles range from 24–50°. There are a spread of Nb–O bond distances ranging from 1.86–2.15 Å. Tl1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Tl–O bond distances ranging from 2.78–3.38 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three Nb5+ and one Tl1+ atom. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two Nb5+ and one Tl1+ atom. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to two Nb5+ and one Tl1+ atom. In the fourth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two Nb5+ and one Tl1+ atom. In the fifth O2- site, O2- is bonded in a bent 150 degrees geometry to one Ti4+ and one Nb5+ atom. In the sixth O2- site, O2- is bonded in a bent 150 degrees geometry to one Ti4+ and one Nb5+ atom. In the seventh O2- site, O2- is bonded in a bent 150 degrees geometry to one Ti4+ and one Nb5+ atom. In the eighth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three Nb5+ and one Tl1+ atom. In the ninth O2- site, O2- is bonded to three Nb5+ and one Tl1+ atom to form distorted edge-sharing ONb3Tl tetrahedra.