DOI: 10.17188/1713575
title: Materials Data on CaAl2Si3(HO3)4 by Materials Project

description: CaAl2Si3(HO3)4 crystallizes in the monoclinic Cc space group. The structure is three-dimensional. Ca2+ is bonded to six O2- atoms to form distorted CaO6 pentagonal pyramids that share corners with two equivalent AlO4 tetrahedra, corners with two SiO4 tetrahedra, an edgeedge with one AlO4 tetrahedra, and an edgeedge with one SiO4 tetrahedra. There are a spread of Ca–O bond distances ranging from 2.30–2.58 Å. There are two inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with four SiO4 tetrahedra and an edgeedge with one CaO6 pentagonal pyramid. There are a spread of Al–O bond distances ranging from 1.75–1.79 Å. In the second Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with two equivalent CaO6 pentagonal pyramids and corners with four SiO4 tetrahedra. There are a spread of Al–O bond distances ranging from 1.75–1.78 Å. There are three inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two AlO4 tetrahedra and corners with two SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.63–1.65 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one CaO6 pentagonal pyramid, a cornercorner with one SiO4 tetrahedra, and corners with three AlO4 tetrahedra. There is two shorter (1.63 Å) and two longer (1.64 Å) Si–O bond length. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one CaO6 pentagonal pyramid, a cornercorner with one SiO4 tetrahedra, corners with three AlO4 tetrahedra, and an edgeedge with one CaO6 pentagonal pyramid. There are a spread of Si–O bond distances ranging from 1.63–1.65 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 0.98 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 1.00 Å. In the third H1+ site, H1+ is bonded in a distorted single-bond geometry to two O2- atoms. There is one shorter (1.00 Å) and one longer (1.68 Å) H–O bond length. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to one Al3+ and one Si4+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to one Al3+, one Si4+, and one H1+ atom. 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 bent 150 degrees geometry to two Si4+ atoms. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, one Al3+, and one Si4+ atom. In the sixth O2- site, O2- is bonded in a bent 120 degrees geometry to one Al3+ and one Si4+ atom. In the seventh O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, one Al3+, and one Si4+ atom. In the eighth O2- site, O2- is bonded in a bent 120 degrees geometry to one Al3+ and one Si4+ atom. In the ninth O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, one Al3+, and one Si4+ atom. In the tenth O2- site, O2- is bonded in a 2-coordinate geometry to one Ca2+, one Al3+, and one Si4+ atom. In the eleventh O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ca2+ and two H1+ atoms. In the twelfth O2- site, O2- is bonded in a distorted water-like geometry to one Ca2+ and two H1+ atoms.