Materials Data on Ti(FeSe2)2 by Materials Project

Abstract

Ti(FeSe2)2 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. Ti4+ is bonded to six Se2- atoms to form distorted TiSe6 octahedra that share corners with six equivalent FeSe6 octahedra, edges with two equivalent TiSe6 octahedra, edges with four equivalent FeSe6 octahedra, and a faceface with one FeSe6 octahedra. The corner-sharing octahedra tilt angles range from 53–58°. There are a spread of Ti–Se bond distances ranging from 2.44–2.74 Å. There are two inequivalent Fe2+ sites. In the first Fe2+ site, Fe2+ is bonded to six Se2- atoms to form FeSe6 octahedra that share corners with six equivalent TiSe6 octahedra, corners with six equivalent FeSe6 octahedra, edges with two equivalent FeSe6 octahedra, a faceface with one TiSe6 octahedra, and a faceface with one FeSe6 octahedra. The corner-sharing octahedra tilt angles range from 49–58°. There are a spread of Fe–Se bond distances ranging from 2.44–2.58 Å. In the second Fe2+ site, Fe2+ is bonded to six Se2- atoms to form FeSe6 octahedra that share corners with six equivalent FeSe6 octahedra, edges with two equivalent FeSe6 octahedra, edges with four equivalent TiSe6 octahedra, and a faceface with one FeSe6 octahedra. The corner-sharing octahedra tilt angles range from 49–56°. There are a spread of Fe–Se bond distances ranging from 2.41–2.59 Å. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 5-coordinate geometry to two equivalent Ti4+ and three Fe2+ atoms. In the second Se2- site, Se2- is bonded in a 5-coordinate geometry to one Ti4+ and four Fe2+ atoms. In the third Se2- site, Se2- is bonded in a 4-coordinate geometry to two equivalent Ti4+ and two Fe2+ atoms. In the fourth Se2- site, Se2- is bonded in a 4-coordinate geometry to one Ti4+ and three Fe2+ atoms.