Materials Data on NaTi2Al5O12 by Materials Project

Abstract

NaTi2Al5O12 crystallizes in the orthorhombic Pbam space group. The structure is three-dimensional. Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are two shorter (2.52 Å) and four longer (2.54 Å) Na–O bond lengths. Ti4+ is bonded to six O2- atoms to form distorted TiO6 octahedra that share corners with four AlO6 octahedra, a cornercorner with one AlO4 tetrahedra, edges with two equivalent TiO6 octahedra, and edges with two equivalent AlO6 octahedra. The corner-sharing octahedra tilt angles range from 49–51°. There are a spread of Ti–O bond distances ranging from 1.83–2.20 Å. There are three inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with four equivalent TiO6 octahedra, corners with four equivalent AlO4 tetrahedra, and edges with two equivalent AlO6 octahedra. The corner-sharing octahedral tilt angles are 51°. There is two shorter (1.91 Å) and four longer (1.93 Å) Al–O bond length. In the second Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two equivalent TiO6 octahedra, corners with four equivalent AlO4 tetrahedra, edges with two equivalent TiO6 octahedra, and edges with two equivalent AlO6 octahedra. The corner-sharing octahedral tilt angles are 49°. There are a spread of Al–O bond distances ranging from 1.89–1.98 Å. In the third Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share a cornercorner with one TiO6 octahedra, corners with six AlO6 octahedra, and corners with two equivalent AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 55–67°. There are a spread of Al–O bond distances ranging from 1.76–1.81 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ti4+ and two equivalent Al3+ atoms. In the second O2- site, O2- is bonded in a trigonal planar geometry to three Al3+ atoms. In the third O2- site, O2- is bonded in a 4-coordinate geometry to one Na1+ and three Al3+ atoms. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Ti4+ and one Al3+ atom. In the fifth O2- site, O2- is bonded to two equivalent Na1+, two equivalent Ti4+, and one Al3+ atom to form a mixture of distorted edge and corner-sharing ONa2Ti2Al square pyramids. In the sixth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Ti4+ and three Al3+ atoms.