Materials Data on Ti4FeSe8 by Materials Project

Ti4FeSe8 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are two inequivalent Ti+3.50+ sites. In the first Ti+3.50+ site, Ti+3.50+ is bonded to six Se2- atoms to form TiSe6 octahedra that share corners with four equivalent FeSe6 octahedra and edges with six TiSe6 octahedra. The corner-sharing octahedra tilt angles range from 49–50°. There are a spread of Ti–Se bond distances ranging from 2.53–2.61 Å. In the second Ti+3.50+ site, Ti+3.50+ is bonded to six Se2- atoms to form TiSe6 octahedra that share corners with two equivalent FeSe6 octahedra, edges with six TiSe6 octahedra, and a faceface with one FeSe6 octahedra. The corner-sharing octahedral tilt angles are 49°. There are a spread of Ti–Se bond distances ranging from 2.55–2.61 Å. Fe2+ is bonded to six Se2- atoms to form FeSe6 octahedra that share corners with twelve TiSe6 octahedra and faces with two equivalent TiSe6 octahedra. The corner-sharing octahedra tilt angles range from 49–50°. All Fe–Se bond lengths are 2.53 Å. There are three inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 3-coordinate geometry to three Ti+3.50+ atoms. In the second Se2- site, Se2- is bonded in a rectangular see-saw-like geometry to three Ti+3.50+ and one Fe2+ atom. In the third Se2- site, Se2- is bonded in a rectangular see-saw-like geometry to three Ti+3.50+ and one Fe2+ atom.