Materials Data on Al2Si2H4O9 by Materials Project

Abstract

Al2Si2O5(OH)4 crystallizes in the monoclinic Cc space group. The structure is two-dimensional and consists of two Al2Si2O5(OH)4 sheets oriented in the (0, 0, 1) direction. there are two inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two SiO4 tetrahedra and edges with three equivalent AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.86–2.06 Å. In the second Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two SiO4 tetrahedra and edges with three equivalent AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.87–2.01 Å. There are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two AlO6 octahedra and corners with three equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 50–55°. There are a spread of Si–O bond distances ranging from 1.62–1.65 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two AlO6 octahedra and corners with three equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 50–56°. There are a spread of Si–O bond distances ranging from 1.62–1.65 Å. There are four inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.97 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.97 Å. In the third H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.96 Å. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.97 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 120 degrees geometry to two Si4+ atoms. In the second O2- site, O2- is bonded in a bent 120 degrees geometry to two Si4+ atoms. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Al3+ and one Si4+ atom. In the fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Al3+ and one Si4+ atom. In the sixth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to two Al3+ and one H1+ atom. In the seventh O2- site, O2- is bonded in a distorted trigonal planar geometry to two Al3+ and one H1+ atom. In the eighth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Al3+ and one H1+ atom. In the ninth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Al3+ and one H1+ atom.