DOI: 10.17188/1695413
title: Materials Data on Mg7TiAl6Si8(H4O19)2 by Materials Project

description: Mg7TiAl6Si8(H4O19)2 crystallizes in the trigonal P3 space group. The structure is three-dimensional. there are three inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six SiO4 tetrahedra and faces with two equivalent TiO6 octahedra. There are three shorter (2.06 Å) and three longer (2.09 Å) Mg–O bond lengths. In the second Mg2+ site, Mg2+ is bonded to six O2- atoms to form distorted MgO6 octahedra that share a cornercorner with one AlO6 octahedra, corners with two equivalent MgO6 octahedra, corners with four SiO4 tetrahedra, edges with two equivalent AlO6 octahedra, and a faceface with one AlO6 octahedra. The corner-sharing octahedra tilt angles range from 31–68°. There are a spread of Mg–O bond distances ranging from 2.03–2.23 Å. In the third Mg2+ site, Mg2+ is bonded to six O2- atoms to form distorted MgO6 octahedra that share a cornercorner with one AlO6 octahedra, corners with two equivalent MgO6 octahedra, corners with four SiO4 tetrahedra, edges with two equivalent AlO6 octahedra, and a faceface with one AlO6 octahedra. The corner-sharing octahedra tilt angles range from 31–67°. There are a spread of Mg–O bond distances ranging from 2.03–2.22 Å. Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with six SiO4 tetrahedra and faces with two equivalent MgO6 octahedra. There is three shorter (1.97 Å) and three longer (1.99 Å) Ti–O bond length. There are two inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to six O2- atoms to form distorted AlO6 octahedra that share a cornercorner with one MgO6 octahedra, corners with two equivalent AlO6 octahedra, corners with four SiO4 tetrahedra, edges with two equivalent MgO6 octahedra, and a faceface with one MgO6 octahedra. The corner-sharing octahedra tilt angles range from 33–67°. There are a spread of Al–O bond distances ranging from 1.85–2.21 Å. In the second Al3+ site, Al3+ is bonded to six O2- atoms to form distorted AlO6 octahedra that share a cornercorner with one MgO6 octahedra, corners with two equivalent AlO6 octahedra, corners with four SiO4 tetrahedra, edges with two equivalent MgO6 octahedra, and a faceface with one MgO6 octahedra. The corner-sharing octahedra tilt angles range from 33–68°. There are a spread of Al–O bond distances ranging from 1.85–2.19 Å. There are four inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three equivalent MgO6 octahedra and corners with three equivalent AlO6 octahedra. The corner-sharing octahedra tilt angles range from 35–60°. There is one shorter (1.61 Å) and three longer (1.62 Å) Si–O bond length. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three equivalent MgO6 octahedra and corners with three equivalent AlO6 octahedra. The corner-sharing octahedra tilt angles range from 35–60°. There is one shorter (1.61 Å) and three longer (1.62 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 TiO6 octahedra, corners with three AlO6 octahedra, and corners with four MgO6 octahedra. The corner-sharing octahedra tilt angles range from 36–64°. There are a spread of Si–O bond distances ranging from 1.64–1.67 Å. In the fourth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one TiO6 octahedra, corners with three AlO6 octahedra, and corners with four MgO6 octahedra. The corner-sharing octahedra tilt angles range from 28–64°. There are a spread of Si–O bond distances ranging from 1.65–1.67 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 0.96 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.96 Å. In the third H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. There are fourteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to one Mg2+, one Al3+, and one Si4+ atom. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to one Mg2+, one Al3+, and one Si4+ atom. In the third O2- site, O2- is bonded in a distorted single-bond geometry to two Mg2+, two Al3+, and one H1+ atom. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to two Mg2+, two Al3+, and one H1+ atom. In the fifth O2- site, O2- is bonded in a linear geometry to one Si4+ and one H1+ atom. In the sixth O2- site, O2- is bonded in a linear geometry to one Si4+ and one H1+ atom. In the seventh O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+, one Ti4+, and one Si4+ atom. In the eighth O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+, one Ti4+, and one Si4+ atom. In the ninth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Mg2+, one Al3+, and one Si4+ atom. In the tenth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Mg2+, one Al3+, and one Si4+ atom. In the eleventh O2- site, O2- is bonded in a trigonal planar geometry to one Mg2+, one Al3+, and one Si4+ atom. In the twelfth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Mg2+, one Al3+, and one Si4+ atom. In the thirteenth O2- site, O2- is bonded in a trigonal planar geometry to one Mg2+, one Al3+, and one Si4+ atom. In the fourteenth O2- site, O2- is bonded in a trigonal planar geometry to one Mg2+, one Al3+, and one Si4+ atom.