DOI: 10.17188/1752335
title: Materials Data on Mg3Al8Fe(Si5O18)2 by Materials Project

description: Mg3FeAl8(Si5O18)2 crystallizes in the monoclinic C2 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 two equivalent AlO4 tetrahedra, corners with four SiO4 tetrahedra, an edgeedge with one SiO4 tetrahedra, and edges with two equivalent AlO4 tetrahedra. There are a spread of Mg–O bond distances ranging from 2.13–2.15 Å. In the second Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with two equivalent AlO4 tetrahedra, corners with four SiO4 tetrahedra, an edgeedge with one SiO4 tetrahedra, and edges with two equivalent AlO4 tetrahedra. There are four shorter (2.14 Å) and two longer (2.15 Å) Mg–O bond lengths. In the third Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with two equivalent AlO4 tetrahedra, corners with four SiO4 tetrahedra, an edgeedge with one SiO4 tetrahedra, and edges with two equivalent AlO4 tetrahedra. There are a spread of Mg–O bond distances ranging from 2.13–2.15 Å. Fe2+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with two equivalent AlO4 tetrahedra, corners with four SiO4 tetrahedra, an edgeedge with one SiO4 tetrahedra, and edges with two equivalent AlO4 tetrahedra. There are four shorter (2.16 Å) and two longer (2.17 Å) Fe–O bond lengths. There are four inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with two MgO6 octahedra and corners with four SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 48°. There is two shorter (1.73 Å) and two longer (1.79 Å) Al–O bond length. In the second Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share a cornercorner with one MgO6 octahedra, a cornercorner with one FeO6 octahedra, and corners with four SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 48–49°. There is two shorter (1.73 Å) and two longer (1.79 Å) Al–O bond length. In the third Al3+ site, Al3+ is bonded to four O2- atoms to form distorted AlO4 tetrahedra that share corners with four SiO4 tetrahedra and edges with two MgO6 octahedra. All Al–O bond lengths are 1.77 Å. In the fourth Al3+ site, Al3+ is bonded to four O2- atoms to form distorted AlO4 tetrahedra that share corners with four SiO4 tetrahedra, an edgeedge with one MgO6 octahedra, and an edgeedge with one FeO6 octahedra. There is one shorter (1.76 Å) and three longer (1.77 Å) Al–O bond length. There are six inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with four AlO4 tetrahedra and edges with two MgO6 octahedra. All Si–O bond lengths are 1.65 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with four AlO4 tetrahedra, an edgeedge with one MgO6 octahedra, and an edgeedge with one FeO6 octahedra. All Si–O bond lengths are 1.65 Å. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two MgO6 octahedra, a cornercorner with one SiO4 tetrahedra, and corners with three AlO4 tetrahedra. The corner-sharing octahedral tilt angles are 43°. There are a spread of Si–O bond distances ranging from 1.59–1.66 Å. In the fourth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one MgO6 octahedra, a cornercorner with one FeO6 octahedra, a cornercorner with one SiO4 tetrahedra, and corners with three AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 43–44°. There are a spread of Si–O bond distances ranging from 1.59–1.66 Å. In the fifth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one MgO6 octahedra, a cornercorner with one FeO6 octahedra, a cornercorner with one SiO4 tetrahedra, and corners with three AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 42–43°. There are a spread of Si–O bond distances ranging from 1.60–1.66 Å. In the sixth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two MgO6 octahedra, a cornercorner with one SiO4 tetrahedra, and corners with three AlO4 tetrahedra. The corner-sharing octahedral tilt angles are 42°. There are a spread of Si–O bond distances ranging from 1.60–1.66 Å. There are eighteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a linear geometry to one Al3+ and one Si4+ atom. In the second O2- site, O2- is bonded in a linear geometry to one Al3+ and one Si4+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+, one Al3+, and one Si4+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+, one Al3+, and one Si4+ atom. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+, one Al3+, and one Si4+ atom. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to one Fe2+, one Al3+, and one Si4+ atom. In the seventh O2- site, O2- is bonded in a linear geometry to two Si4+ atoms. In the eighth O2- site, O2- is bonded in a linear geometry to two Si4+ atoms. In the ninth O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+, one Al3+, and one Si4+ atom. In the tenth O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+, one Al3+, and one Si4+ atom. In the eleventh O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+, one Al3+, and one Si4+ atom. In the twelfth O2- site, O2- is bonded in a 3-coordinate geometry to one Fe2+, one Al3+, and one Si4+ atom. In the thirteenth O2- site, O2- is bonded in a linear geometry to one Al3+ and one Si4+ atom. In the fourteenth O2- site, O2- is bonded in a linear geometry to one Al3+ and one Si4+ atom. In the fifteenth O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+, one Al3+, and one Si4+ atom. In the sixteenth O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+, one Al3+, and one Si4+ atom. In the seventeenth O2- site, O2- is bonded in a 3-coordinate geometry to one Fe2+, one Al3+, and one Si4+ atom. In the eighteenth O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+, one Al3+, and one Si4+ atom.