Materials Data on RbAl11O17 by Materials Project

RbAl11O17 crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Rb1+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are six shorter (2.93 Å) and three longer (3.26 Å) Rb–O bond lengths. There are four inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with five AlO4 tetrahedra and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.82–2.05 Å. In the second Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with six equivalent AlO6 octahedra and a cornercorner with one AlO4 tetrahedra. The corner-sharing octahedral tilt angles are 54°. There is one shorter (1.73 Å) and three longer (1.80 Å) Al–O bond length. In the third Al3+ site, Al3+ is bonded to four O2- atoms to form corner-sharing AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 54–58°. There is three shorter (1.82 Å) and one longer (1.84 Å) Al–O bond length. In the fourth Al3+ site, Al3+ is bonded to six equivalent O2- atoms to form AlO6 octahedra that share corners with six equivalent AlO4 tetrahedra and edges with six equivalent AlO6 octahedra. All Al–O bond lengths are 1.91 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Rb1+ and three Al3+ atoms. In the third O2- site, O2- is bonded in a linear geometry to three equivalent Rb1+ and two equivalent Al3+ atoms. In the fourth O2- site, O2- is bonded in a trigonal non-coplanar geometry to three equivalent Al3+ atoms. In the fifth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms.