Materials Data on Al5HO8 by Materials Project

Abstract

HAl5O8 crystallizes in the hexagonal P6_3mc space group. The structure is three-dimensional. there are three inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to one H1+ and six O2- atoms to form AlHO6 pentagonal bipyramids that share corners with two equivalent AlO6 octahedra, corners with three equivalent AlO4 trigonal pyramids, an edgeedge with one AlO6 octahedra, edges with two equivalent AlHO6 pentagonal bipyramids, and faces with two equivalent AlHO6 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 53°. The Al–H bond length is 1.74 Å. There are a spread of Al–O bond distances ranging from 1.90–1.95 Å. In the second Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six equivalent AlHO6 pentagonal bipyramids, corners with three equivalent AlO4 trigonal pyramids, and edges with three equivalent AlHO6 pentagonal bipyramids. There is three shorter (1.87 Å) and three longer (2.04 Å) Al–O bond length. In the third Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 trigonal pyramids that share corners with three equivalent AlO6 octahedra and corners with nine equivalent AlHO6 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 51°. There is three shorter (1.85 Å) and one longer (1.89 Å) Al–O bond length. H1+ is bonded in a single-bond geometry to three equivalent Al3+ and one O2- atom. The H–O bond length is 1.02 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to three equivalent Al3+ and one H1+ atom. In the second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Al3+ atoms. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms. In the fourth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Al3+ atoms.