Materials Data on NaTi8O13 by Materials Project
NaTi8O13 crystallizes in the trigonal R-3 space group. The structure is three-dimensional. Na1+ is bonded to twelve O2- atoms to form NaO12 cuboctahedra that share corners with eighteen TiO6 octahedra and faces with eight TiO6 octahedra. The corner-sharing octahedra tilt angles range from 38–50°. There are six shorter (2.78 Å) and six longer (3.07 Å) Na–O bond lengths. There are two inequivalent Ti+3.12+ sites. In the first Ti+3.12+ site, Ti+3.12+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with two equivalent NaO12 cuboctahedra, corners with four TiO6 octahedra, edges with seven TiO6 octahedra, and a faceface with one NaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–14°. There are a spread of Ti–O bond distances ranging from 1.95–2.13 Å. In the second Ti+3.12+ site, Ti+3.12+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with three equivalent NaO12 cuboctahedra, corners with three equivalent TiO6 octahedra, edges with six equivalent TiO6 octahedra, and a faceface with one NaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 11°. There are three shorter (1.91 Å) and three longer (2.12 Å) Ti–O bond lengths. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Na1+ and four Ti+3.12+ atoms. In the second O2- site, O2- is bonded in an octahedral geometry to six equivalent Ti+3.12+ atoms. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+ and three Ti+3.12+ atoms.