Materials Data on Li2Ti4O9 by Materials Project
Li2Ti4O9 is Ilmenite-like structured and crystallizes in the trigonal P-3c1 space group. The structure is three-dimensional. Li1+ is bonded to six O2- atoms to form LiO6 octahedra that share corners with nine TiO6 octahedra, edges with three equivalent TiO6 octahedra, and a faceface with one LiO6 octahedra. The corner-sharing octahedra tilt angles range from 51–63°. There are three shorter (2.08 Å) and three longer (2.28 Å) Li–O bond lengths. There are two inequivalent Ti4+ sites. In the first Ti4+ site, Ti4+ is bonded to six equivalent O2- atoms to form distorted TiO6 octahedra that share corners with three equivalent TiO6 octahedra, corners with six equivalent LiO6 octahedra, edges with three equivalent TiO6 octahedra, and a faceface with one TiO6 octahedra. The corner-sharing octahedra tilt angles range from 43–63°. There is three shorter (1.88 Å) and three longer (2.11 Å) Ti–O bond length. In the second Ti4+ site, Ti4+ is bonded to six O2- atoms to form distorted TiO6 octahedra that share corners with three equivalent LiO6 octahedra, corners with six TiO6 octahedra, edges with three equivalent LiO6 octahedra, and a faceface with one TiO6 octahedra. The corner-sharing octahedra tilt angles range from 43–51°. There is three shorter (1.88 Å) and three longer (2.11 Å) Ti–O bond length. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to two equivalent Li1+ and two equivalent Ti4+ atoms to form a mixture of distorted edge and corner-sharing OLi2Ti2 trigonal pyramids. In the second O2- site, O2- is bonded in a distorted see-saw-like geometry to one Li1+ and three Ti4+ atoms.