DOI: 10.17188/1284797
title: Materials Data on Mg4Al9Cu(SiO4)9 by Materials Project

description: Mg4CuAl9(SiO4)9 crystallizes in the monoclinic P2 space group. The structure is three-dimensional. there are two inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with two AlO4 tetrahedra, corners with four SiO4 tetrahedra, an edgeedge with one SiO4 tetrahedra, and edges with two AlO4 tetrahedra. There are a spread of Mg–O bond distances ranging from 2.08–2.17 Å. In the second Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with two AlO4 tetrahedra, corners with four SiO4 tetrahedra, and edges with three AlO4 tetrahedra. There are a spread of Mg–O bond distances ranging from 2.02–2.21 Å. Cu1+ is bonded in a distorted rectangular see-saw-like geometry to four O2- atoms. There are two shorter (2.31 Å) and two longer (2.49 Å) Cu–O bond lengths. There are seven 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, a cornercorner with one AlO4 tetrahedra, and corners with three SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 41–49°. There are a spread of Al–O bond distances ranging from 1.73–1.81 Å. In the second Al3+ site, Al3+ is bonded to four O2- atoms to form distorted AlO4 tetrahedra that share corners with four AlO4 tetrahedra and edges with two equivalent MgO6 octahedra. There is two shorter (1.76 Å) and two longer (1.78 Å) Al–O bond length. In the third Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with two MgO6 octahedra, a cornercorner with one AlO4 tetrahedra, and corners with three SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 40–48°. There are a spread of Al–O bond distances ranging from 1.73–1.79 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 and edges with two equivalent MgO6 octahedra. There is two shorter (1.76 Å) and two longer (1.77 Å) Al–O bond length. In the fifth 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 equivalent MgO6 octahedra. There is two shorter (1.76 Å) and two longer (1.77 Å) Al–O bond length. In the sixth 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 equivalent MgO6 octahedra. There is two shorter (1.77 Å) and two longer (1.79 Å) Al–O bond length. In the seventh 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 equivalent MgO6 octahedra. There is two shorter (1.77 Å) and two longer (1.78 Å) Al–O bond length. There are five inequivalent Si4+ sites. In the first 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 octahedra tilt angles range from 41–42°. 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 MgO6 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 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 octahedra tilt angles range from 43–44°. There are a spread of Si–O bond distances ranging from 1.60–1.66 Å. In the fourth 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 octahedra tilt angles range from 44–45°. There are a spread of Si–O bond distances ranging from 1.62–1.65 Å. In the fifth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with four AlO4 tetrahedra and edges with two equivalent MgO6 octahedra. There is two shorter (1.64 Å) and two longer (1.65 Å) Si–O bond length. There are eighteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Cu1+, 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 distorted trigonal planar geometry to one Mg2+ and two Al3+ atoms. 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 distorted T-shaped geometry to one Mg2+ and two Al3+ atoms. In the seventh O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+, one Al3+, and one Si4+ atom. In the eighth O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+, one Al3+, and one Si4+ atom. In the ninth O2- site, O2- is bonded in a linear geometry to one Al3+ and one Si4+ atom. In the tenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Cu1+, one Al3+, and one Si4+ atom. In the eleventh O2- site, O2- is bonded in a distorted trigonal planar 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 Mg2+, one Al3+, and one Si4+ atom. In the thirteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Mg2+, one Al3+, and one Si4+ atom. In the fourteenth O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+, 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 linear geometry to two Si4+ atoms. In the eighteenth O2- site, O2- is bonded in a linear geometry to two Si4+ atoms.