Materials Data on TlIn5Se8 by Materials Project
TlIn5Se8 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Tl1+ is bonded in a distorted body-centered cubic geometry to eight Se2- atoms. There are four shorter (3.38 Å) and four longer (3.97 Å) Tl–Se bond lengths. There are three inequivalent In3+ sites. In the first In3+ site, In3+ is bonded to four Se2- atoms to form distorted InSe4 tetrahedra that share corners with three equivalent InSe6 octahedra, corners with two equivalent InSe4 tetrahedra, and edges with two equivalent InSe6 octahedra. The corner-sharing octahedra tilt angles range from 68–80°. There are a spread of In–Se bond distances ranging from 2.58–2.68 Å. In the second In3+ site, In3+ is bonded to six Se2- atoms to form distorted InSe6 octahedra that share corners with two equivalent InSe6 octahedra, corners with three equivalent InSe4 tetrahedra, and edges with four equivalent InSe6 octahedra. The corner-sharing octahedral tilt angles are 47°. There are a spread of In–Se bond distances ranging from 2.73–3.18 Å. In the third In3+ site, In3+ is bonded to six Se2- atoms to form InSe6 octahedra that share corners with four equivalent InSe6 octahedra, edges with two equivalent InSe6 octahedra, and edges with four equivalent InSe4 tetrahedra. The corner-sharing octahedral tilt angles are 47°. There are four shorter (2.80 Å) and two longer (2.84 Å) In–Se bond lengths. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a trigonal non-coplanar geometry to three In3+ atoms. In the second Se2- site, Se2- is bonded in a 5-coordinate geometry to two equivalent Tl1+ and three In3+ atoms. In the third Se2- site, Se2- is bonded in a 3-coordinate geometry to two equivalent Tl1+ and three equivalent In3+ atoms. In the fourth Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to four In3+ atoms.