Materials Data on AlSiHO4 by Materials Project
AlSiO3OH crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two equivalent AlO6 octahedra, corners with four equivalent SiO6 octahedra, an edgeedge with one AlO6 octahedra, and edges with two equivalent SiO6 octahedra. The corner-sharing octahedra tilt angles range from 50–54°. There are a spread of Al–O bond distances ranging from 1.89–1.97 Å. Si4+ is bonded to six O2- atoms to form distorted SiO6 octahedra that share corners with two equivalent SiO6 octahedra, corners with four equivalent AlO6 octahedra, an edgeedge with one SiO6 octahedra, and edges with two equivalent AlO6 octahedra. The corner-sharing octahedra tilt angles range from 48–54°. There are a spread of Si–O bond distances ranging from 1.75–2.17 Å. H1+ is bonded in a distorted bent 150 degrees geometry to two O2- atoms. There is one shorter (1.02 Å) and one longer (1.60 Å) H–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to one Al3+ and two equivalent Si4+ atoms. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to one Al3+ and two equivalent Si4+ atoms. In the third O2- site, O2- is bonded to two equivalent Al3+, one Si4+, and one H1+ atom to form edge-sharing OAl2SiH tetrahedra. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent Al3+, one Si4+, and one H1+ atom.