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DOE OSTI2020

Materials Data on MgAl2O4 by Materials Project

MgAl2O4 is Spinel-like structured and crystallizes in the trigonal R3m space group. The structure is three-dimensional. there are eight inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with three equivalent MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 57–61°. There is three shorter (1.92 Å) and one longer (2.01 Å) Mg–O bond length. In the second Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with three equivalent MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 56–63°. There is three shorter (1.93 Å) and one longer (1.97 Å) Mg–O bond length. In the third Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with three equivalent MgO4 tetrahedra, corners with three equivalent AlO4 tetrahedra, and edges with six AlO6 octahedra. There are three shorter (2.00 Å) and three longer (2.10 Å) Mg–O bond lengths. In the fourth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 58–60°. There is one shorter (1.93 Å) and three longer (1.96 Å) Mg–O bond length. In the fifth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with three equivalent MgO4 tetrahedra, corners with three equivalent AlO4 tetrahedra, and edges with six AlO6 octahedra. There are three shorter (2.03 Å) and three longer (2.08 Å) Mg–O bond lengths. In the sixth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 59–60°. There is one shorter (1.95 Å) and three longer (1.96 Å) Mg–O bond length. In the seventh Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 58–62°. There is three shorter (1.97 Å) and one longer (2.00 Å) Mg–O bond length. In the eighth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 59–62°. There is three shorter (1.96 Å) and one longer (2.01 Å) Mg–O bond length. There are eight inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three MgO4 tetrahedra, corners with three AlO4 tetrahedra, edges with two MgO6 octahedra, and edges with four equivalent AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.88–2.04 Å. In the second Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share a cornercorner with one AlO4 tetrahedra, corners with five MgO4 tetrahedra, an edgeedge with one MgO6 octahedra, and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.88–2.07 Å. In the third Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.92–1.95 Å. In the fourth Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with three equivalent MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 55–60°. There is three shorter (1.84 Å) and one longer (1.85 Å) Al–O bond length. In the fifth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There is three shorter (1.91 Å) and three longer (1.95 Å) Al–O bond length. In the sixth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two equivalent AlO4 tetrahedra, corners with four MgO4 tetrahedra, an edgeedge with one MgO6 octahedra, and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.92–1.98 Å. In the seventh Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There is three shorter (1.92 Å) and three longer (1.94 Å) Al–O bond length. In the eighth Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with three equivalent MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 55–61°. There is three shorter (1.83 Å) and one longer (1.86 Å) Al–O bond length. There are sixteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+ and two equivalent Al3+ atoms. In the second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three equivalent Al3+ atoms. In the third O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three Al3+ atoms. In the fourth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+ and two equivalent Al3+ atoms. In the fifth O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form distorted corner-sharing OMgAl3 trigonal pyramids. In the sixth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Al3+ atoms. In the seventh O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 tetrahedra. In the eighth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the ninth O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the tenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Al3+ atoms. In the eleventh O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the twelfth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the thirteenth O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the fourteenth O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the fifteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Al3+ atoms. In the sixteenth O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form corner-sharing OMgAl3 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on MgAl2O4 by Materials Project

MgAl2O4 is Spinel-like structured and crystallizes in the trigonal P3m1 space group. The structure is three-dimensional. there are six inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with three equivalent MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 56–61°. There is three shorter (1.93 Å) and one longer (2.00 Å) Mg–O bond length. In the second Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with three equivalent MgO4 tetrahedra, corners with three equivalent AlO4 tetrahedra, and edges with six AlO6 octahedra. There are three shorter (2.01 Å) and three longer (2.10 Å) Mg–O bond lengths. In the third Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with three equivalent MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 56–63°. There is three shorter (1.93 Å) and one longer (1.97 Å) Mg–O bond length. In the fourth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with three equivalent MgO4 tetrahedra, corners with three equivalent AlO4 tetrahedra, and edges with six AlO6 octahedra. There are three shorter (2.03 Å) and three longer (2.08 Å) Mg–O bond lengths. In the fifth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 58–59°. There is one shorter (1.93 Å) and three longer (1.96 Å) Mg–O bond length. In the sixth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 58–61°. There are three shorter (1.97 Å) and one longer (2.05 Å) Mg–O bond lengths. There are six inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three MgO4 tetrahedra, corners with three AlO4 tetrahedra, edges with two MgO6 octahedra, and edges with four equivalent AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.88–2.04 Å. In the second Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share a cornercorner with one AlO4 tetrahedra, corners with five MgO4 tetrahedra, an edgeedge with one MgO6 octahedra, and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.88–2.07 Å. In the third Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There is three shorter (1.91 Å) and three longer (1.94 Å) Al–O bond length. In the fourth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two equivalent AlO4 tetrahedra, corners with four MgO4 tetrahedra, an edgeedge with one MgO6 octahedra, and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.92–1.99 Å. In the fifth Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with three equivalent MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 55–60°. There is three shorter (1.84 Å) and one longer (1.86 Å) Al–O bond length. In the sixth Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with three equivalent MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 55–61°. There is three shorter (1.82 Å) and one longer (1.87 Å) Al–O bond length. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+ and two equivalent Al3+ atoms. In the second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three equivalent Al3+ atoms. In the third O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three Al3+ atoms. In the fourth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+ and two equivalent Al3+ atoms. In the fifth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Al3+ atoms. In the sixth O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form distorted corner-sharing OMgAl3 trigonal pyramids. In the seventh O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the eighth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 tetrahedra. In the ninth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Al3+ atoms. In the tenth O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the eleventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Al3+ atoms. In the twelfth O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form corner-sharing OMgAl3 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on MgAl2O4 by Materials Project

MgAl2O4 is Spinel-like structured and crystallizes in the trigonal P3m1 space group. The structure is three-dimensional. there are six inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with three equivalent MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 57–62°. There is three shorter (1.93 Å) and one longer (2.01 Å) Mg–O bond length. In the second Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedral tilt angles are 59°. There is one shorter (1.96 Å) and three longer (1.97 Å) Mg–O bond length. In the third Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with three equivalent MgO4 tetrahedra, corners with three equivalent AlO4 tetrahedra, and edges with six AlO6 octahedra. There are three shorter (2.02 Å) and three longer (2.11 Å) Mg–O bond lengths. In the fourth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 59–62°. There is three shorter (1.96 Å) and one longer (2.01 Å) Mg–O bond length. In the fifth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 58–60°. There is one shorter (1.93 Å) and three longer (1.96 Å) Mg–O bond length. In the sixth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 59–62°. There is three shorter (1.97 Å) and one longer (2.00 Å) Mg–O bond length. There are six inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with three equivalent MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 55–61°. All Al–O bond lengths are 1.83 Å. In the second Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two equivalent AlO4 tetrahedra, corners with four MgO4 tetrahedra, an edgeedge with one MgO6 octahedra, and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.92–1.98 Å. In the third Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.93–1.95 Å. In the fourth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There is three shorter (1.92 Å) and three longer (1.94 Å) Al–O bond length. In the fifth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share a cornercorner with one AlO4 tetrahedra, corners with five MgO4 tetrahedra, an edgeedge with one MgO6 octahedra, and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.89–2.06 Å. In the sixth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There is three shorter (1.92 Å) and three longer (1.95 Å) Al–O bond length. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Al3+ atoms. In the second O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form corner-sharing OMgAl3 tetrahedra. In the third O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 trigonal pyramids. In the fourth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 trigonal pyramids. In the fifth O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 trigonal pyramids. In the sixth O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 trigonal pyramids. In the seventh O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 tetrahedra. In the eighth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 trigonal pyramids. In the ninth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Al3+ atoms. In the tenth O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 trigonal pyramids. In the eleventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+ and two equivalent Al3+ atoms. In the twelfth O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form distorted corner-sharing OMgAl3 trigonal pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on MgAl2O4 by Materials Project

MgAl2O4 is Spinel-like structured and crystallizes in the trigonal R3m space group. The structure is three-dimensional. there are two inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with three equivalent MgO6 octahedra and corners with nine equivalent AlO6 octahedra. The corner-sharing octahedra tilt angles range from 56–62°. There is three shorter (1.93 Å) and one longer (1.96 Å) Mg–O bond length. In the second Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with three equivalent MgO4 tetrahedra, corners with three equivalent AlO4 tetrahedra, and edges with six equivalent AlO6 octahedra. There are three shorter (2.02 Å) and three longer (2.07 Å) Mg–O bond lengths. There are two inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three equivalent MgO4 tetrahedra, corners with three equivalent AlO4 tetrahedra, edges with two equivalent MgO6 octahedra, and edges with four equivalent AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.87–2.04 Å. In the second Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with three equivalent MgO6 octahedra and corners with nine equivalent AlO6 octahedra. The corner-sharing octahedra tilt angles range from 57–59°. There is three shorter (1.83 Å) and one longer (1.91 Å) Al–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+ and two equivalent Al3+ atoms. In the second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three equivalent Al3+ atoms. In the third O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Al3+ atoms. In the fourth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Al3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on MgAl2O4 by Materials Project

MgAl2O4 is Spinel structured and crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. Mg2+ is bonded to four equivalent O2- atoms to form MgO4 tetrahedra that share corners with twelve equivalent AlO6 octahedra. The corner-sharing octahedral tilt angles are 59°. All Mg–O bond lengths are 1.96 Å. Al3+ is bonded to six equivalent O2- atoms to form AlO6 octahedra that share corners with six equivalent MgO4 tetrahedra and edges with six equivalent AlO6 octahedra. All Al–O bond lengths are 1.94 Å. O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 trigonal pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on MgAl2O4 by Materials Project

MgAl2O4 is Spinel-like structured and crystallizes in the orthorhombic Imma space group. The structure is three-dimensional. Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six equivalent AlO4 tetrahedra, edges with two equivalent MgO6 octahedra, and edges with four equivalent AlO6 octahedra. There are four shorter (2.03 Å) and two longer (2.06 Å) Mg–O bond lengths. 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 six equivalent MgO6 octahedra and corners with six equivalent AlO6 octahedra. The corner-sharing octahedra tilt angles range from 54–57°. There is two shorter (1.79 Å) and two longer (1.85 Å) Al–O bond length. In the second Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six equivalent AlO4 tetrahedra, edges with two equivalent AlO6 octahedra, and edges with four equivalent MgO6 octahedra. There is two shorter (1.90 Å) and four longer (1.97 Å) Al–O bond length. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a rectangular see-saw-like geometry to two equivalent Mg2+ and two Al3+ atoms. In the second O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Al3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg3Al14O24 by Materials Project

Mg3Al14O24 is beta indium sulfide-derived structured and crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are three inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 55–64°. There is one shorter (1.95 Å) and three longer (1.97 Å) Mg–O bond length. In the second Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with eleven AlO6 octahedra. The corner-sharing octahedra tilt angles range from 54–63°. There are a spread of Mg–O bond distances ranging from 1.90–1.97 Å. In the third Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 58–65°. There are three shorter (2.00 Å) and one longer (2.01 Å) Mg–O bond lengths. There are eleven inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three MgO4 tetrahedra, corners with three AlO4 tetrahedra, and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.87–1.99 Å. In the second Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three MgO4 tetrahedra, corners with three AlO4 tetrahedra, and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.86–1.98 Å. In the third Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two equivalent AlO4 tetrahedra, corners with four MgO4 tetrahedra, and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.88–2.01 Å. In the fourth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three MgO4 tetrahedra, corners with three AlO4 tetrahedra, and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.88–2.00 Å. In the fifth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share a cornercorner with one AlO4 tetrahedra, corners with five MgO4 tetrahedra, and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.87–2.04 Å. In the sixth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two equivalent MgO4 tetrahedra, corners with four AlO4 tetrahedra, and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.87–2.00 Å. In the seventh Al3+ site, Al3+ is bonded to four O2- atoms to form corner-sharing AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 51–58°. There are a spread of Al–O bond distances ranging from 1.76–1.82 Å. In the eighth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three MgO4 tetrahedra, corners with three AlO4 tetrahedra, and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.89–1.98 Å. In the ninth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three MgO4 tetrahedra, corners with three AlO4 tetrahedra, and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.81–2.14 Å. In the tenth Al3+ site, Al3+ is bonded to four O2- atoms to form corner-sharing AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 52–61°. There is two shorter (1.76 Å) and two longer (1.84 Å) Al–O bond length. In the eleventh Al3+ site, Al3+ is bonded to four O2- atoms to form corner-sharing AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 52–62°. There are a spread of Al–O bond distances ranging from 1.76–1.85 Å. There are eighteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Al3+ atoms. In the second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three Al3+ atoms. In the third O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Al3+ atoms. In the fourth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form corner-sharing OMgAl3 tetrahedra. In the fifth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form distorted corner-sharing OMgAl3 tetrahedra. In the sixth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the seventh O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 tetrahedra. In the eighth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 tetrahedra. In the ninth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the tenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Al3+ atoms. In the eleventh O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 tetrahedra. In the twelfth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Al3+ atoms. In the thirteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms. In the fourteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms. In the fifteenth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form distorted corner-sharing OMgAl3 trigonal pyramids. In the sixteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms. In the seventeenth O2- site, O2- is bonded in a trigonal planar geometry to one Mg2+ and two equivalent Al3+ atoms. In the eighteenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Al3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on MgAl2O4 by Materials Project

MgAl2O4 is Spinel-like structured and crystallizes in the trigonal P3m1 space group. The structure is three-dimensional. there are twelve inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with three equivalent MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 57–61°. There is three shorter (1.93 Å) and one longer (2.01 Å) Mg–O bond length. In the second Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with three equivalent MgO4 tetrahedra, corners with three equivalent AlO4 tetrahedra, and edges with six AlO6 octahedra. There are three shorter (2.01 Å) and three longer (2.10 Å) Mg–O bond lengths. In the third Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with three equivalent MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 57–62°. There is three shorter (1.93 Å) and one longer (1.97 Å) Mg–O bond length. In the fourth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with three equivalent MgO4 tetrahedra, corners with three equivalent AlO4 tetrahedra, and edges with six AlO6 octahedra. There are three shorter (2.03 Å) and three longer (2.08 Å) Mg–O bond lengths. In the fifth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 58–60°. There is one shorter (1.94 Å) and three longer (1.95 Å) Mg–O bond length. In the sixth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 59–60°. All Mg–O bond lengths are 1.96 Å. In the seventh Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 59–61°. There is three shorter (1.98 Å) and one longer (1.99 Å) Mg–O bond length. In the eighth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 59–60°. There is one shorter (1.95 Å) and three longer (1.96 Å) Mg–O bond length. In the ninth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 59–60°. There is three shorter (1.96 Å) and one longer (1.97 Å) Mg–O bond length. In the tenth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedral tilt angles are 59°. All Mg–O bond lengths are 1.96 Å. In the eleventh Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 59–60°. There is three shorter (1.96 Å) and one longer (1.98 Å) Mg–O bond length. In the twelfth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 59–62°. There is three shorter (1.96 Å) and one longer (2.01 Å) Mg–O bond length. There are twelve inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three MgO4 tetrahedra, corners with three AlO4 tetrahedra, edges with two MgO6 octahedra, and edges with four equivalent AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.88–2.04 Å. In the second Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share a cornercorner with one AlO4 tetrahedra, corners with five MgO4 tetrahedra, an edgeedge with one MgO6 octahedra, and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.89–2.07 Å. In the third Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with three equivalent MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 55–60°. There is three shorter (1.84 Å) and one longer (1.85 Å) Al–O bond length. In the fourth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. All Al–O bond lengths are 1.93 Å. In the fifth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There is two shorter (1.93 Å) and four longer (1.94 Å) Al–O bond length. In the sixth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. All Al–O bond lengths are 1.94 Å. In the seventh Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There is three shorter (1.93 Å) and three longer (1.94 Å) Al–O bond length. In the eighth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.93–1.95 Å. In the ninth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There is three shorter (1.92 Å) and three longer (1.95 Å) Al–O bond length. In the tenth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two equivalent AlO4 tetrahedra, corners with four MgO4 tetrahedra, an edgeedge with one MgO6 octahedra, and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.92–1.99 Å. In the eleventh Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There is three shorter (1.92 Å) and three longer (1.94 Å) Al–O bond length. In the twelfth Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with three equivalent MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 55–61°. There is three shorter (1.83 Å) and one longer (1.86 Å) Al–O bond length. There are twenty-four inequivalent O2- sites. In the first O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+ and two equivalent Al3+ atoms. In the second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three equivalent Al3+ atoms. In the third O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+ and two equivalent Al3+ atoms. In the fourth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three Al3+ atoms. In the fifth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Al3+ atoms. In the sixth O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form distorted corner-sharing OMgAl3 trigonal pyramids. In the seventh O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 trigonal pyramids. In the eighth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 tetrahedra. In the ninth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the tenth O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 trigonal pyramids. In the eleventh O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 trigonal pyramids. In the twelfth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 trigonal pyramids. In the thirteenth O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 trigonal pyramids. In the fourteenth O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 trigonal pyramids. In the fifteenth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 trigonal pyramids. In the sixteenth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 trigonal pyramids. In the seventeenth O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 trigonal pyramids. In the eighteenth O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 tetrahedra. In the nineteenth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 trigonal pyramids. In the twentieth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 trigonal pyramids. In the twenty-first O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 tetrahedra. In the twenty-second O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 trigonal pyramids. In the twenty-third O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Al3+ atoms. In the twenty-fourth O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form corner-sharing OMgAl3 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on MgAl2O4 by Materials Project

MgAl2O4 is Spinel-like structured and crystallizes in the trigonal R3m space group. The structure is three-dimensional. there are eight inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with three equivalent MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 57–62°. There is three shorter (1.93 Å) and one longer (2.01 Å) Mg–O bond length. In the second Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with three equivalent MgO4 tetrahedra, corners with three equivalent AlO4 tetrahedra, and edges with six AlO6 octahedra. There are three shorter (2.02 Å) and three longer (2.11 Å) Mg–O bond lengths. In the third Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 58–60°. There is one shorter (1.94 Å) and three longer (1.95 Å) Mg–O bond length. In the fourth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 59–60°. There is one shorter (1.95 Å) and three longer (1.97 Å) Mg–O bond length. In the fifth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 59–61°. There is three shorter (1.98 Å) and one longer (1.99 Å) Mg–O bond length. In the sixth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedral tilt angles are 59°. All Mg–O bond lengths are 1.96 Å. In the seventh Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 59–60°. There is three shorter (1.96 Å) and one longer (1.97 Å) Mg–O bond length. In the eighth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 59–62°. There is three shorter (1.96 Å) and one longer (2.01 Å) Mg–O bond length. There are eight inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share a cornercorner with one AlO4 tetrahedra, corners with five MgO4 tetrahedra, an edgeedge with one MgO6 octahedra, and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.89–2.07 Å. In the second Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. All Al–O bond lengths are 1.93 Å. In the third Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There is two shorter (1.93 Å) and four longer (1.94 Å) Al–O bond length. In the fourth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There is three shorter (1.93 Å) and three longer (1.95 Å) Al–O bond length. In the fifth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.93–1.95 Å. In the sixth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There is three shorter (1.92 Å) and three longer (1.94 Å) Al–O bond length. In the seventh Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two equivalent AlO4 tetrahedra, corners with four MgO4 tetrahedra, an edgeedge with one MgO6 octahedra, and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.92–1.98 Å. In the eighth Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with three equivalent MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 55–61°. There is one shorter (1.82 Å) and three longer (1.83 Å) Al–O bond length. There are sixteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+ and two equivalent Al3+ atoms. In the second O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form distorted corner-sharing OMgAl3 trigonal pyramids. In the third O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 tetrahedra. In the fourth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the fifth O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the sixth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Al3+ atoms. In the seventh O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the eighth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the ninth O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the tenth O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the eleventh O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the twelfth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the thirteenth O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 tetrahedra. In the fourteenth O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the fifteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Al3+ atoms. In the sixteenth O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form corner-sharing OMgAl3 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on MgAl6O10 by Materials Project

MgAl6O10 is beta indium sulfide-derived structured and crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are four inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 57–61°. There is three shorter (1.93 Å) and one longer (2.03 Å) Mg–O bond length. In the second Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 56–62°. There is three shorter (1.94 Å) and one longer (2.03 Å) Mg–O bond length. In the third Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 58–63°. There are a spread of Mg–O bond distances ranging from 1.92–1.97 Å. In the fourth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 57–64°. There is one shorter (1.93 Å) and three longer (1.96 Å) Mg–O bond length. There are nineteen inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to four O2- atoms to form corner-sharing AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 53–58°. There is three shorter (1.78 Å) and one longer (1.80 Å) Al–O bond length. In the second Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six AlO4 tetrahedra and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.85–1.99 Å. In the third Al3+ site, Al3+ is bonded to four O2- atoms to form corner-sharing AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 50–58°. There are a spread of Al–O bond distances ranging from 1.78–1.86 Å. In the fourth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six AlO4 tetrahedra and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.84–2.05 Å. In the fifth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six AlO4 tetrahedra and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.85–2.05 Å. In the sixth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six AlO4 tetrahedra and edges with four AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.90–2.00 Å. In the seventh Al3+ site, Al3+ is bonded to four O2- atoms to form corner-sharing AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 54–63°. There are a spread of Al–O bond distances ranging from 1.73–1.88 Å. In the eighth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three MgO4 tetrahedra, corners with three AlO4 tetrahedra, and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.90–1.96 Å. In the ninth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six AlO4 tetrahedra and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.80–2.11 Å. In the tenth Al3+ site, Al3+ is bonded to four O2- atoms to form corner-sharing AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 56–61°. There is one shorter (1.78 Å) and three longer (1.87 Å) Al–O bond length. In the eleventh Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three MgO4 tetrahedra, corners with three AlO4 tetrahedra, and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.89–1.99 Å. In the twelfth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.90–1.96 Å. In the thirteenth Al3+ site, Al3+ is bonded to four O2- atoms to form corner-sharing AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 46–60°. There are a spread of Al–O bond distances ranging from 1.76–1.87 Å. In the fourteenth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There is three shorter (1.88 Å) and three longer (1.97 Å) Al–O bond length. In the fifteenth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.90–1.96 Å. In the sixteenth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three MgO4 tetrahedra, corners with three AlO4 tetrahedra, and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.88–1.98 Å. In the seventeenth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three MgO4 tetrahedra, corners with three AlO4 tetrahedra, and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.88–1.98 Å. In the eighteenth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There is three shorter (1.87 Å) and three longer (1.98 Å) Al–O bond length. In the nineteenth Al3+ site, Al3+ is bonded to four O2- atoms to form corner-sharing AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 54–60°. There are a spread of Al–O bond distances ranging from 1.75–1.89 Å. There are thirty inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms. In the second O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the third O2- site, O2- is bonded in a trigonal planar geometry to three Al3+ atoms. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms. In the fifth O2- site, O2- is bonded to four Al3+ atoms to form distorted edge-sharing OAl4 trigonal pyramids. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms. In the seventh O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Al3+ atoms. In the eighth O2- site, O2- is bonded to four Al3+ atoms to form distorted edge-sharing OAl4 tetrahedra. In the ninth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the tenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the eleventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the twelfth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms. In the thirteenth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form distorted corner-sharing OMgAl3 tetrahedra. In the fourteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms. In the fifteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the sixteenth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the seventeenth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 tetrahedra. In the eighteenth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 tetrahedra. In the nineteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the twentieth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 tetrahedra. In the twenty-first O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the twenty-second O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form distorted OMgAl3 tetrahedra that share corners with three OMgAl3 tetrahedra, corners with two equivalent OMgAl3 trigonal pyramids, edges with two OMgAl3 tetrahedra, and an edgeedge with one OAl4 trigonal pyramid. In the twenty-third O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three Al3+ atoms. In the twenty-fourth O2- site, O2- is bonded to four Al3+ atoms to form a mixture of distorted edge and corner-sharing OAl4 trigonal pyramids. In the twenty-fifth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three Al3+ atoms. In the twenty-sixth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form distorted corner-sharing OMgAl3 trigonal pyramids. In the twenty-seventh O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form distorted OMgAl3 tetrahedra that share corners with three OMgAl3 tetrahedra, corners with two equivalent OMgAl3 trigonal pyramids, edges with two equivalent OMgAl3 tetrahedra, and an edgeedge with one OAl4 trigonal pyramid. In the twenty-eighth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms. In the twenty-ninth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms. In the thirtieth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form distorted OMgAl3 trigonal pyramids that share corners with six OMgAl3 tetrahedra and corners with three equivalent OAl4 trigonal pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on MgAl6O10 by Materials Project

MgAl6O10 is beta indium sulfide-derived structured and crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are four inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with eleven AlO6 octahedra. The corner-sharing octahedra tilt angles range from 55–66°. There is one shorter (1.90 Å) and three longer (1.99 Å) Mg–O bond length. In the second Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with eleven AlO6 octahedra. The corner-sharing octahedra tilt angles range from 54–67°. There is one shorter (1.90 Å) and three longer (1.99 Å) Mg–O bond length. In the third Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 57–62°. There is one shorter (1.92 Å) and three longer (1.95 Å) Mg–O bond length. In the fourth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 58–61°. There is three shorter (1.93 Å) and one longer (2.03 Å) Mg–O bond length. There are nineteen inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to four O2- atoms to form corner-sharing AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 45–59°. There are a spread of Al–O bond distances ranging from 1.75–1.86 Å. In the second Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share a cornercorner with one MgO4 tetrahedra, corners with five AlO4 tetrahedra, and edges with four AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.81–2.04 Å. In the third Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two equivalent MgO4 tetrahedra, corners with four AlO4 tetrahedra, and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.87–1.96 Å. In the fourth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two equivalent MgO4 tetrahedra, corners with four AlO4 tetrahedra, and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.87–1.98 Å. In the fifth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three equivalent MgO4 tetrahedra, corners with three equivalent AlO4 tetrahedra, and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.85–2.02 Å. In the sixth Al3+ site, Al3+ is bonded to four O2- atoms to form corner-sharing AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 45–59°. There are a spread of Al–O bond distances ranging from 1.75–1.85 Å. In the seventh Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share a cornercorner with one MgO4 tetrahedra, corners with five AlO4 tetrahedra, and edges with four AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.81–2.03 Å. In the eighth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six AlO4 tetrahedra and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.80–2.11 Å. In the ninth Al3+ site, Al3+ is bonded to four O2- atoms to form corner-sharing AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 50–59°. There are a spread of Al–O bond distances ranging from 1.77–1.89 Å. In the tenth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share a cornercorner with one AlO4 tetrahedra, corners with five MgO4 tetrahedra, and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.87–1.96 Å. In the eleventh Al3+ site, Al3+ is bonded to four O2- atoms to form corner-sharing AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 54–64°. There are a spread of Al–O bond distances ranging from 1.75–1.90 Å. In the twelfth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three equivalent MgO4 tetrahedra, corners with three equivalent AlO4 tetrahedra, and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.85–2.02 Å. In the thirteenth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three MgO4 tetrahedra, corners with three AlO4 tetrahedra, and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.90–1.95 Å. In the fourteenth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share a cornercorner with one AlO4 tetrahedra, corners with five MgO4 tetrahedra, and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.88–1.97 Å. In the fifteenth Al3+ site, Al3+ is bonded to four O2- atoms to form corner-sharing AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 50–59°. There are a spread of Al–O bond distances ranging from 1.77–1.87 Å. In the sixteenth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three MgO4 tetrahedra, corners with three AlO4 tetrahedra, and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.89–1.99 Å. In the seventeenth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.89–1.96 Å. In the eighteenth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six AlO4 tetrahedra and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.80–2.12 Å. In the nineteenth Al3+ site, Al3+ is bonded to four O2- atoms to form corner-sharing AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 53–64°. There are a spread of Al–O bond distances ranging from 1.75–1.88 Å. There are thirty inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms. In the second O2- site, O2- is bonded in a trigonal non-coplanar geometry to one Mg2+ and two equivalent Al3+ atoms. In the third O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the fourth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three Al3+ atoms. In the fifth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms. In the seventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the eighth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms. In the ninth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three Al3+ atoms. In the tenth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms. In the eleventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the twelfth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Al3+ atoms. In the thirteenth O2- site, O2- is bonded in a distorted trigonal pyramidal geometry to four Al3+ atoms. In the fourteenth O2- site, O2- is bonded in a trigonal non-coplanar geometry to one Mg2+ and two equivalent Al3+ atoms. In the fifteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the sixteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the seventeenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three Al3+ atoms. In the eighteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms. In the nineteenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three Al3+ atoms. In the twentieth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms. In the twenty-first O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three Al3+ atoms. In the twenty-second O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 tetrahedra. In the twenty-third O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 tetrahedra. In the twenty-fourth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the twenty-fifth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the twenty-sixth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 trigonal pyramids. In the twenty-seventh O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 tetrahedra. In the twenty-eighth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the twenty-ninth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the thirtieth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form distorted corner-sharing OMgAl3 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on MgAl2O4 by Materials Project

MgAl2O4 is Spinel-like structured and crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are seven 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 MgO4 tetrahedra, corners with four equivalent AlO4 tetrahedra, edges with two equivalent MgO6 octahedra, and edges with four AlO6 octahedra. There are a spread of Mg–O bond distances ranging from 1.97–2.12 Å. In the second Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with two equivalent MgO6 octahedra and corners with ten AlO6 octahedra. The corner-sharing octahedra tilt angles range from 55–63°. There are a spread of Mg–O bond distances ranging from 1.94–2.00 Å. In the third Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 58–60°. There is one shorter (1.95 Å) and three longer (1.96 Å) Mg–O bond length. In the fourth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 59–60°. All Mg–O bond lengths are 1.96 Å. In the fifth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 59–61°. There is three shorter (1.97 Å) and one longer (1.98 Å) Mg–O bond length. In the sixth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 59–60°. All Mg–O bond lengths are 1.96 Å. In the seventh Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 59–60°. All Mg–O bond lengths are 1.96 Å. There are twelve inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with four equivalent MgO6 octahedra and corners with eight AlO6 octahedra. The corner-sharing octahedra tilt angles range from 50–59°. There are a spread of Al–O bond distances ranging from 1.79–1.83 Å. In the second Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three equivalent MgO4 tetrahedra, corners with three equivalent AlO4 tetrahedra, edges with two equivalent MgO6 octahedra, and edges with four AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.91–1.97 Å. In the third Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two equivalent MgO4 tetrahedra, corners with four equivalent AlO4 tetrahedra, edges with two equivalent AlO6 octahedra, and edges with four equivalent MgO6 octahedra. There is two shorter (1.81 Å) and four longer (2.04 Å) Al–O bond length. In the fourth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share a cornercorner with one AlO4 tetrahedra, corners with five MgO4 tetrahedra, and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.91–2.00 Å. In the fifth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share a cornercorner with one AlO4 tetrahedra, corners with five MgO4 tetrahedra, and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.92–2.00 Å. In the sixth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There is one shorter (1.93 Å) and five longer (1.94 Å) Al–O bond length. In the seventh Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There is three shorter (1.93 Å) and three longer (1.94 Å) Al–O bond length. In the eighth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There is two shorter (1.93 Å) and four longer (1.94 Å) Al–O bond length. In the ninth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. All Al–O bond lengths are 1.94 Å. In the tenth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. All Al–O bond lengths are 1.94 Å. In the eleventh Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. All Al–O bond lengths are 1.94 Å. In the twelfth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six equivalent MgO4 tetrahedra and edges with six AlO6 octahedra. All Al–O bond lengths are 1.94 Å. There are twenty inequivalent O2- sites. In the first O2- site, O2- is bonded in a rectangular see-saw-like geometry to two equivalent Mg2+ and two Al3+ atoms. In the second O2- site, O2- is bonded to three Mg2+ and one Al3+ atom to form distorted corner-sharing OMg3Al tetrahedra. In the third O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Al3+ atoms. In the fourth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three Al3+ atoms. In the fifth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form distorted corner-sharing OMgAl3 trigonal pyramids. In the sixth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Al3+ atoms. In the seventh O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form distorted OMgAl3 tetrahedra that share corners with two OMgAl3 tetrahedra, corners with six OMgAl3 trigonal pyramids, edges with two OMgAl3 tetrahedra, and an edgeedge with one OAl4 trigonal pyramid. In the eighth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the ninth O2- site, O2- is bonded to four Al3+ atoms to form a mixture of distorted edge and corner-sharing OAl4 trigonal pyramids. In the tenth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the eleventh O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the twelfth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form distorted OMgAl3 tetrahedra that share corners with two equivalent OMgAl3 tetrahedra, corners with six OMgAl3 trigonal pyramids, edges with two equivalent OMgAl3 tetrahedra, and an edgeedge with one OAl4 trigonal pyramid. In the thirteenth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the fourteenth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the fifteenth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the sixteenth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the seventeenth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the eighteenth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the nineteenth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the twentieth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on MgAl2O4 by Materials Project

MgAl2O4 is Spinel-like structured and crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are eight inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with three equivalent MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 56–62°. There is three shorter (1.93 Å) and one longer (2.00 Å) Mg–O bond length. In the second Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with three equivalent MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 57–63°. There is three shorter (1.94 Å) and one longer (1.98 Å) Mg–O bond length. In the third Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with three equivalent MgO4 tetrahedra, corners with three equivalent AlO4 tetrahedra, and edges with six AlO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.03–2.08 Å. In the fourth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with two equivalent AlO4 tetrahedra, corners with four MgO4 tetrahedra, and edges with six AlO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.01–2.09 Å. In the fifth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share a cornercorner with one MgO6 octahedra and corners with eleven AlO6 octahedra. The corner-sharing octahedra tilt angles range from 57–65°. There are a spread of Mg–O bond distances ranging from 1.97–1.99 Å. In the sixth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share a cornercorner with one MgO6 octahedra and corners with eleven AlO6 octahedra. The corner-sharing octahedra tilt angles range from 56–62°. There are a spread of Mg–O bond distances ranging from 1.97–1.99 Å. In the seventh Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with three equivalent MgO4 tetrahedra, corners with three equivalent AlO4 tetrahedra, and edges with six AlO6 octahedra. There are three shorter (2.02 Å) and three longer (2.09 Å) Mg–O bond lengths. In the eighth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with two equivalent MgO6 octahedra and corners with ten AlO6 octahedra. The corner-sharing octahedra tilt angles range from 56–63°. There are a spread of Mg–O bond distances ranging from 1.94–2.00 Å. There are twelve inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three MgO4 tetrahedra, corners with three AlO4 tetrahedra, edges with two MgO6 octahedra, and edges with four equivalent AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.88–2.03 Å. In the second Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three MgO4 tetrahedra, corners with three AlO4 tetrahedra, edges with two MgO6 octahedra, and edges with four AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.88–2.03 Å. In the third Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two AlO4 tetrahedra, corners with four MgO4 tetrahedra, an edgeedge with one MgO6 octahedra, and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.86–2.06 Å. In the fourth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two AlO4 tetrahedra, corners with four MgO4 tetrahedra, an edgeedge with one MgO6 octahedra, and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.86–2.05 Å. In the fifth Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with two equivalent MgO6 octahedra and corners with ten AlO6 octahedra. The corner-sharing octahedra tilt angles range from 54–61°. There are a spread of Al–O bond distances ranging from 1.80–1.85 Å. In the sixth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two equivalent AlO4 tetrahedra, corners with four MgO4 tetrahedra, edges with two equivalent MgO6 octahedra, and edges with four AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.88–2.05 Å. In the seventh Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with three equivalent MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 54–59°. There are a spread of Al–O bond distances ranging from 1.83–1.86 Å. In the eighth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three equivalent MgO4 tetrahedra, corners with three equivalent AlO4 tetrahedra, an edgeedge with one MgO6 octahedra, and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.90–2.02 Å. In the ninth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two equivalent AlO4 tetrahedra, corners with four MgO4 tetrahedra, an edgeedge with one MgO6 octahedra, and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.91–1.99 Å. In the tenth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two equivalent AlO4 tetrahedra, corners with four MgO4 tetrahedra, an edgeedge with one MgO6 octahedra, and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.91–1.99 Å. In the eleventh Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra, an edgeedge with one MgO6 octahedra, and edges with five AlO6 octahedra. There is two shorter (1.89 Å) and four longer (1.95 Å) Al–O bond length. In the twelfth Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with three equivalent MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 55–60°. There is three shorter (1.82 Å) and one longer (1.88 Å) Al–O bond length. There are twenty-four inequivalent O2- sites. In the first O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+ and two Al3+ atoms. In the second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three Al3+ atoms. In the third O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+ and two equivalent Al3+ atoms. In the fourth O2- site, O2- is bonded to two Mg2+ and two Al3+ atoms to form distorted OMg2Al2 trigonal pyramids that share corners with four OMgAl3 tetrahedra, corners with two OMg2Al2 trigonal pyramids, and edges with two OMg2Al2 trigonal pyramids. In the fifth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Al3+ atoms. In the sixth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three Al3+ atoms. In the seventh O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Al3+ atoms. In the eighth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the ninth O2- site, O2- is bonded to two Mg2+ and two equivalent Al3+ atoms to form distorted OMg2Al2 trigonal pyramids that share corners with four OMgAl3 tetrahedra, corners with two equivalent OMg2Al2 trigonal pyramids, and edges with two equivalent OMg2Al2 trigonal pyramids. In the tenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Al3+ atoms. In the eleventh O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form distorted OMgAl3 tetrahedra that share corners with two equivalent OMgAl3 tetrahedra, corners with four OMg2Al2 trigonal pyramids, and edges with two equivalent OMgAl3 tetrahedra. In the twelfth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form distorted OMgAl3 tetrahedra that share corners with two OMgAl3 tetrahedra, corners with four OMg2Al2 trigonal pyramids, and edges with two OMgAl3 tetrahedra. In the thirteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the fourteenth O2- site, O2- is bonded to two Mg2+ and two equivalent Al3+ atoms to form distorted corner-sharing OMg2Al2 tetrahedra. In the fifteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the sixteenth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form distorted OMgAl3 trigonal pyramids that share corners with three OMg2Al2 tetrahedra, corners with three OMgAl3 trigonal pyramids, and edges with three OMgAl3 trigonal pyramids. In the seventeenth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form distorted OMgAl3 trigonal pyramids that share corners with three OMg2Al2 tetrahedra and corners with three OMgAl3 trigonal pyramids. In the eighteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+ and two equivalent Al3+ atoms. In the nineteenth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 trigonal pyramids. In the twentieth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+ and two Al3+ atoms. In the twenty-first O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form distorted OMgAl3 trigonal pyramids that share corners with three OMg2Al2 tetrahedra, corners with three OMgAl3 trigonal pyramids, and edges with three OMgAl3 trigonal pyramids. In the twenty-second O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Al3+ atoms. In the twenty-third O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Al3+ atoms. In the twenty-fourth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form corner-sharing OMgAl3 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg5Al34O56 by Materials Project

Mg5Al34O56 is beta indium sulfide-derived structured and crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are five inequivalent Mg sites. In the first Mg site, Mg is bonded to four O atoms to form MgO4 tetrahedra that share corners with eleven AlO6 octahedra. The corner-sharing octahedra tilt angles range from 52–71°. There are a spread of Mg–O bond distances ranging from 1.86–2.02 Å. In the second Mg site, Mg is bonded to four O atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 55–67°. There are a spread of Mg–O bond distances ranging from 1.87–1.98 Å. In the third Mg site, Mg is bonded to four O atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 56–61°. There are a spread of Mg–O bond distances ranging from 1.93–1.96 Å. In the fourth Mg site, Mg is bonded to four O atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 54–61°. There are a spread of Mg–O bond distances ranging from 1.92–2.01 Å. In the fifth Mg site, Mg is bonded to four O atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 50–64°. There are a spread of Mg–O bond distances ranging from 1.89–2.27 Å. There are twenty-seven inequivalent Al sites. In the first Al site, Al is bonded to four O atoms to form corner-sharing AlO4 trigonal pyramids. The corner-sharing octahedra tilt angles range from 59–68°. There are a spread of Al–O bond distances ranging from 1.72–2.12 Å. In the second Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with four AlO4 tetrahedra, corners with two equivalent AlO4 trigonal pyramids, and edges with three AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.82–2.12 Å. In the third Al site, Al is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Al–O bond distances ranging from 1.72–2.35 Å. In the fourth Al site, Al is bonded to four O atoms to form corner-sharing AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 48–62°. There are a spread of Al–O bond distances ranging from 1.78–1.86 Å. In the fifth Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with six AlO4 tetrahedra and edges with four AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.89–2.03 Å. In the sixth Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with six AlO4 tetrahedra and edges with four AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.87–2.14 Å. In the seventh Al site, Al is bonded to four O atoms to form corner-sharing AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 53–58°. There are a spread of Al–O bond distances ranging from 1.78–1.85 Å. In the eighth Al site, Al is bonded to six O atoms to form AlO6 octahedra that share a cornercorner with one MgO4 tetrahedra, corners with five AlO4 tetrahedra, and edges with four AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.83–2.11 Å. In the ninth Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with six AlO4 tetrahedra and edges with four AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.91–2.04 Å. In the tenth Al site, Al is bonded to four O atoms to form corner-sharing AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 53–64°. There are a spread of Al–O bond distances ranging from 1.75–1.93 Å. In the eleventh Al site, Al is bonded to six O atoms to form AlO6 octahedra that share a cornercorner with one AlO4 tetrahedra, corners with five MgO4 tetrahedra, and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.84–2.00 Å. In the twelfth Al site, Al is bonded to six O atoms to form AlO6 octahedra that share a cornercorner with one AlO4 tetrahedra, corners with five MgO4 tetrahedra, and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.84–2.00 Å. In the thirteenth Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with three equivalent MgO4 tetrahedra, corners with three equivalent AlO4 tetrahedra, and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.80–2.12 Å. In the fourteenth Al site, Al is bonded to four O atoms to form corner-sharing AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 54–60°. There is three shorter (1.81 Å) and one longer (1.87 Å) Al–O bond length. In the fifteenth Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with two equivalent AlO4 tetrahedra, corners with four MgO4 tetrahedra, and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.86–2.07 Å. In the sixteenth Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with two equivalent AlO4 tetrahedra, corners with four MgO4 tetrahedra, and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.86–2.07 Å. In the seventeenth Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.82–2.06 Å. In the eighteenth Al site, Al is bonded to four O atoms to form corner-sharing AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 43–61°. There are a spread of Al–O bond distances ranging from 1.75–1.99 Å. In the nineteenth Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with three MgO4 tetrahedra, corners with three AlO4 tetrahedra, and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.90–1.99 Å. In the twentieth Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with three equivalent MgO4 tetrahedra, corners with three equivalent AlO4 tetrahedra, and edges with six AlO6 octahedra. There is three shorter (1.93 Å) and three longer (1.94 Å) Al–O bond length. In the twenty-first Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with three MgO4 tetrahedra, corners with three AlO4 tetrahedra, and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.90–1.99 Å. In the twenty-second Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with two equivalent MgO4 tetrahedra, corners with three AlO4 tetrahedra, a cornercorner with one AlO4 trigonal pyramid, and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.87–2.05 Å. In the twenty-third Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with two equivalent MgO4 tetrahedra, corners with three AlO4 tetrahedra, a cornercorner with one AlO4 trigonal pyramid, and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.87–2.04 Å. In the twenty-fourth Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with three equivalent MgO4 tetrahedra, corners with three equivalent AlO4 tetrahedra, and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.84–2.02 Å. In the twenty-fifth Al site, Al is bonded to four O atoms to form corner-sharing AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 54–59°. There are a spread of Al–O bond distances ranging from 1.83–1.90 Å. In the twenty-sixth Al site, Al is bonded to four O atoms to form corner-sharing AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 55–61°. There are a spread of Al–O bond distances ranging from 1.80–1.89 Å. In the twenty-seventh Al site, Al is bonded to four O atoms to form corner-sharing AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 51–57°. There are a spread of Al–O bond distances ranging from 1.69–1.96 Å. There are forty-two inequivalent O sites. In the first O site, O is bonded in a rectangular see-saw-like geometry to one Mg and three Al atoms. In the second O site, O is bonded to four Al atoms to form a mixture of distorted edge and corner-sharing OAl4 tetrahedra. In the third O site, O is bonded to four Al atoms to form a mixture of distorted edge and corner-sharing OAl4 trigonal pyramids. In the fourth O site, O is bonded in a rectangular see-saw-like geometry to four Al atoms. In the fifth O site, O is bonded in a 3-coordinate geometry to three Al atoms. In the sixth O site, O is bonded in a trigonal non-coplanar geometry to three Al atoms. In the seventh O site, O is bonded in a rectangular see-saw-like geometry to four Al atoms. In the eighth O site, O is bonded in a distorted trigonal planar geometry to three Al atoms. In the ninth O site, O is bonded in a distorted rectangular see-saw-like geometry to four Al atoms. In the tenth O site, O is bonded in a trigonal planar geometry to three Al atoms. In the eleventh O site, O is bonded in a distorted trigonal planar geometry to three Al atoms. In the twelfth O site, O is bonded in a distorted trigonal planar geometry to three Al atoms. In the thirteenth O site, O is bonded in a rectangular see-saw-like geometry to four Al atoms. In the fourteenth O site, O is bonded in a distorted trigonal planar geometry to three Al atoms. In the fifteenth O site, O is bonded in a rectangular see-saw-like geometry to four Al atoms. In the sixteenth O site, O is bonded in a distorted trigonal planar geometry to three Al atoms. In the seventeenth O site, O is bonded in a trigonal planar geometry to one Mg and two equivalent Al atoms. In the eighteenth O site, O is bonded in a trigonal planar geometry to three Al atoms. In the nineteenth O site, O is bonded in a rectangular see-saw-like geometry to four Al atoms. In the twentieth O site, O is bonded to one Mg and three Al atoms to form distorted OMgAl3 trigonal pyramids that share corners with two equivalent OAl4 tetrahedra, corners with two OMgAl3 trigonal pyramids, and edges with two OMgAl3 trigonal pyramids. In the twenty-first O site, O is bonded in a rectangular see-saw-like geometry to four Al atoms. In the twenty-second O site, O is bonded in a distorted rectangular see-saw-like geometry to one Mg and three Al atoms. In the twenty-third O site, O is bonded in a distorted trigonal planar geometry to three Al atoms. In the twenty-fourth O site, O is bonded in a trigonal planar geometry to three Al atoms. In the twenty-fifth O site, O is bonded to one Mg and three Al atoms to form distorted OMgAl3 trigonal pyramids that share corners with two equivalent OAl4 tetrahedra, corners with two equivalent OMgAl3 trigonal pyramids, and edges with two equivalent OMgAl3 trigonal pyramids. In the twenty-sixth O site, O is bonded in a distorted rectangular see-saw-like geometry to one Mg and three Al atoms. In the twenty-seventh O site, O is bonded in a rectangular see-saw-like geometry to one Mg and three Al atoms. In the twenty-eighth O site, O is bonded in a distorted rectangular see-saw-like geometry to one Mg and three Al atoms. In the twenty-ninth O site, O is bonded to four Al atoms to form distorted corner-sharing OAl4 tetrahedra. In the thirtieth O site, O is bonded in a rectangular see-saw-like geometry to one Mg and three Al atoms. In the thirty-first O site, O is bonded to one Mg and three Al atoms to form distorted corner-sharing OMgAl3 trigonal pyramids. In the thirty-second O site, O is bonded to one Mg and three Al atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the thirty-third O site, O is bonded in a rectangular see-saw-like geometry to four Al atoms. In the thirty-fourth O site, O is bonded in a

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg7Al22O40 by Materials Project

Mg7Al22O40 is Spinel-like structured and crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are seven inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share a cornercorner with one MgO6 octahedra and corners with eleven AlO6 octahedra. The corner-sharing octahedra tilt angles range from 56–65°. There are a spread of Mg–O bond distances ranging from 1.96–1.99 Å. In the second Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with two equivalent MgO4 tetrahedra, corners with four AlO4 tetrahedra, and edges with six AlO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.00–2.05 Å. In the third Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 58–63°. There is one shorter (1.93 Å) and three longer (1.97 Å) Mg–O bond length. In the fourth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with three MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 57–62°. There is three shorter (1.94 Å) and one longer (1.98 Å) Mg–O bond length. In the fifth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with two equivalent AlO4 tetrahedra, corners with four MgO4 tetrahedra, and edges with six AlO6 octahedra. There are a spread of Mg–O bond distances ranging from 1.99–2.09 Å. In the sixth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with two equivalent MgO6 octahedra and corners with ten AlO6 octahedra. The corner-sharing octahedra tilt angles range from 56–62°. There are a spread of Mg–O bond distances ranging from 1.92–1.98 Å. In the seventh Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 57–61°. There is three shorter (1.93 Å) and one longer (2.03 Å) Mg–O bond length. There are seventeen inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to four O2- atoms to form corner-sharing AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 45–60°. There are a spread of Al–O bond distances ranging from 1.77–1.87 Å. In the second Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with two equivalent MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 56–60°. There are a spread of Al–O bond distances ranging from 1.77–1.90 Å. In the third Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six AlO4 tetrahedra and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.80–2.12 Å. In the fourth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six AlO4 tetrahedra and edges with four AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.90–2.01 Å. In the fifth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six AlO4 tetrahedra, an edgeedge with one MgO6 octahedra, and edges with four AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.85–2.06 Å. In the sixth Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with three MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 56–59°. There are a spread of Al–O bond distances ranging from 1.81–1.86 Å. In the seventh Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two equivalent MgO4 tetrahedra, corners with four AlO4 tetrahedra, edges with two equivalent MgO6 octahedra, and edges with four AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.85–2.02 Å. In the eighth Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share a cornercorner with one MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 49–58°. There are a spread of Al–O bond distances ranging from 1.78–1.88 Å. In the ninth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three equivalent MgO4 tetrahedra, corners with three equivalent AlO4 tetrahedra, edges with two MgO6 octahedra, and edges with four AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.88–2.01 Å. In the tenth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two equivalent AlO4 tetrahedra, corners with four MgO4 tetrahedra, edges with two equivalent MgO6 octahedra, and edges with four AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.87–2.07 Å. In the eleventh Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra, an edgeedge with one MgO6 octahedra, and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.87–1.98 Å. In the twelfth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.91–1.97 Å. In the thirteenth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There is three shorter (1.89 Å) and three longer (1.97 Å) Al–O bond length. In the fourteenth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.90–1.96 Å. In the fifteenth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three MgO4 tetrahedra, corners with three AlO4 tetrahedra, and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.89–1.99 Å. In the sixteenth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three MgO4 tetrahedra, corners with three AlO4 tetrahedra, and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.90–1.97 Å. In the seventeenth Al3+ site, Al3+ is bonded to four O2- atoms to form corner-sharing AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 54–63°. There are a spread of Al–O bond distances ranging from 1.73–1.89 Å. There are thirty inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms. In the third O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the fourth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the fifth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms. In the seventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Al3+ atoms. In the eighth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Al3+ atoms. In the ninth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Al3+ atoms. In the tenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Al3+ atoms. In the eleventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Al3+ atoms. In the twelfth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Mg2+ and two Al3+ atoms. In the thirteenth O2- site, O2- is bonded to two Mg2+ and two equivalent Al3+ atoms to form corner-sharing OMg2Al2 tetrahedra. In the fourteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Al3+ atoms. In the fifteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the sixteenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three Al3+ atoms. In the seventeenth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form distorted corner-sharing OMgAl3 trigonal pyramids. In the eighteenth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form distorted corner-sharing OMgAl3 trigonal pyramids. In the nineteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+ and two Al3+ atoms. In the twentieth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+ and two equivalent Al3+ atoms. In the twenty-first O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three Al3+ atoms. In the twenty-second O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 tetrahedra. In the twenty-third O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the twenty-fourth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the twenty-fifth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 tetrahedra. In the twenty-sixth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the twenty-seventh O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 tetrahedra. In the twenty-eighth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the twenty-ninth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the thirtieth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form distorted corner-sharing OMgAl3 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on MgAl2O4 by Materials Project

MgAl2O4 is Spinel-like structured and crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are fourteen inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with two equivalent MgO6 octahedra and corners with ten AlO6 octahedra. The corner-sharing octahedra tilt angles range from 52–65°. There are a spread of Mg–O bond distances ranging from 1.92–2.01 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 MgO4 tetrahedra, and edges with six AlO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.00–2.09 Å. In the third Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with three MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 56–62°. There are a spread of Mg–O bond distances ranging from 1.92–2.00 Å. In the fourth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with three MgO4 tetrahedra, corners with three AlO4 tetrahedra, and edges with six AlO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.01–2.08 Å. In the fifth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with three MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 56–62°. There are a spread of Mg–O bond distances ranging from 1.91–1.98 Å. In the sixth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share a cornercorner with one MgO6 octahedra and corners with eleven AlO6 octahedra. The corner-sharing octahedra tilt angles range from 57–66°. There are a spread of Mg–O bond distances ranging from 1.97–2.00 Å. In the seventh Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with three MgO4 tetrahedra, corners with three AlO4 tetrahedra, and edges with six AlO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.01–2.08 Å. In the eighth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 58–62°. There are a spread of Mg–O bond distances ranging from 1.93–1.98 Å. In the ninth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with three MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 56–62°. There is three shorter (1.93 Å) and one longer (1.98 Å) Mg–O bond length. In the tenth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with two equivalent AlO4 tetrahedra, corners with four MgO4 tetrahedra, and edges with six AlO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.00–2.09 Å. In the eleventh Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with two equivalent MgO6 octahedra and corners with ten AlO6 octahedra. The corner-sharing octahedra tilt angles range from 55–63°. There are a spread of Mg–O bond distances ranging from 1.93–1.98 Å. In the twelfth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 58–62°. There are a spread of Mg–O bond distances ranging from 1.93–1.98 Å. In the thirteenth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 56–61°. There are a spread of Mg–O bond distances ranging from 1.94–2.01 Å. In the fourteenth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 57–63°. There is three shorter (1.95 Å) and one longer (2.04 Å) Mg–O bond length. There are twenty-one inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with three MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 55–61°. There are a spread of Al–O bond distances ranging from 1.82–1.89 Å. In the second Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two AlO4 tetrahedra, corners with four MgO4 tetrahedra, edges with two equivalent MgO6 octahedra, and edges with four AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.85–2.03 Å. In the third Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three equivalent MgO4 tetrahedra, corners with three equivalent AlO4 tetrahedra, edges with two MgO6 octahedra, and edges with four AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.89–2.01 Å. In the fourth Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with three MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 55–60°. There are a spread of Al–O bond distances ranging from 1.83–1.89 Å. In the fifth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three MgO4 tetrahedra, corners with three AlO4 tetrahedra, edges with two equivalent MgO6 octahedra, and edges with four AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.86–2.06 Å. In the sixth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three equivalent MgO4 tetrahedra, corners with three equivalent AlO4 tetrahedra, edges with two MgO6 octahedra, and edges with four AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.89–2.01 Å. In the seventh Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with three MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 55–60°. There are a spread of Al–O bond distances ranging from 1.82–1.88 Å. In the eighth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three MgO4 tetrahedra, corners with three AlO4 tetrahedra, edges with two equivalent MgO6 octahedra, and edges with four AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.86–2.07 Å. In the ninth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three equivalent MgO4 tetrahedra, corners with three equivalent AlO4 tetrahedra, edges with two MgO6 octahedra, and edges with four AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.88–2.02 Å. In the tenth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two equivalent AlO4 tetrahedra, corners with four MgO4 tetrahedra, edges with two equivalent MgO6 octahedra, and edges with four AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.87–2.08 Å. In the eleventh Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra, an edgeedge with one MgO6 octahedra, and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.88–1.98 Å. In the twelfth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.92–1.97 Å. In the thirteenth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.91–1.97 Å. In the fourteenth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.89–1.98 Å. In the fifteenth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.91–1.97 Å. In the sixteenth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two equivalent AlO4 tetrahedra, corners with four MgO4 tetrahedra, and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.91–1.99 Å. In the seventeenth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.91–1.96 Å. In the eighteenth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There is three shorter (1.90 Å) and three longer (1.97 Å) Al–O bond length. In the nineteenth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two equivalent AlO4 tetrahedra, corners with four MgO4 tetrahedra, and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.91–2.01 Å. In the twentieth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three equivalent MgO4 tetrahedra, corners with three equivalent AlO4 tetrahedra, an edgeedge with one MgO6 octahedra, and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.83–2.08 Å. In the twenty-first Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share a cornercorner with one MgO6 octahedra and corners with eleven AlO6 octahedra. The corner-sharing octahedra tilt angles range from 53–61°. There are a spread of Al–O bond distances ranging from 1.75–1.88 Å. There are forty-two inequivalent O2- sites. In the first O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the second O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the third O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the fourth O2- site, O2- is bonded to four Al3+ atoms to form distorted OAl4 trigonal pyramids that share corners with nine OMgAl3 trigonal pyramids, an edgeedge with one OMgAl3 tetrahedra, and edges with two equivalent OAl4 trigonal pyramids. In the fifth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form OMgAl3 tetrahedra that share corners with twelve OMgAl3 trigonal pyramids and edges with three OAl4 trigonal pyramids. In the sixth O2- site, O2- is bonded to four Al3+ atoms to form distorted OAl4 trigonal pyramids that share corners with nine OMgAl3 trigonal pyramids, an edgeedge with one OMgAl3 tetrahedra, and edges with two OAl4 trigonal pyramids. In the seventh O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 tetrahedra. In the eighth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form distorted OMgAl3 trigonal pyramids that share corners with three equivalent OMgAl3 tetrahedra, corners with seven OAl4 trigonal pyramids, and edges with three OMgAl3 trigonal pyramids. In the ninth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OMgAl3 trigonal pyramids. In the tenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+ and two Al3+ atoms. In the eleventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Al3+ atoms. In t

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on MgAl2O4 by Materials Project

MgAl2O4 is Spinel-like structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are fourteen inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share a cornercorner with one MgO4 tetrahedra, corners with five AlO4 tetrahedra, edges with two equivalent MgO6 octahedra, and edges with four AlO6 octahedra. There are a spread of Mg–O bond distances ranging from 1.97–2.10 Å. In the second Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share a cornercorner with one MgO4 tetrahedra, corners with five AlO4 tetrahedra, edges with two equivalent MgO6 octahedra, and edges with four AlO6 octahedra. There are a spread of Mg–O bond distances ranging from 1.95–2.13 Å. In the third Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with four MgO6 octahedra and corners with eight AlO6 octahedra. The corner-sharing octahedra tilt angles range from 55–63°. There are a spread of Mg–O bond distances ranging from 1.94–1.97 Å. In the fourth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with three MgO4 tetrahedra, corners with three AlO4 tetrahedra, and edges with six AlO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.01–2.07 Å. In the fifth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with three MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 56–62°. There is three shorter (1.93 Å) and one longer (1.96 Å) Mg–O bond length. In the sixth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with three MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 56–62°. There is three shorter (1.93 Å) and one longer (1.96 Å) Mg–O bond length. In the seventh Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with three MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 56–62°. There are a spread of Mg–O bond distances ranging from 1.92–1.97 Å. In the eighth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with three MgO4 tetrahedra, corners with three AlO4 tetrahedra, and edges with six AlO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.01–2.06 Å. In the ninth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with three MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 56–62°. There are a spread of Mg–O bond distances ranging from 1.91–1.97 Å. In the tenth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with three MgO4 tetrahedra, corners with three AlO4 tetrahedra, and edges with six AlO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.01–2.07 Å. In the eleventh Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with three MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 56–62°. There are a spread of Mg–O bond distances ranging from 1.93–1.98 Å. In the twelfth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with three MgO4 tetrahedra, corners with three AlO4 tetrahedra, and edges with six AlO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.01–2.07 Å. In the thirteenth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with three MgO4 tetrahedra, corners with three AlO4 tetrahedra, and edges with six AlO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.01–2.07 Å. In the fourteenth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with two equivalent MgO4 tetrahedra, corners with four AlO4 tetrahedra, and edges with six AlO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.00–2.06 Å. There are twenty-eight inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with five MgO6 octahedra and corners with seven AlO6 octahedra. The corner-sharing octahedra tilt angles range from 50–60°. There are a spread of Al–O bond distances ranging from 1.78–1.83 Å. In the second Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six AlO4 tetrahedra, edges with three MgO6 octahedra, and edges with three AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.88–2.03 Å. In the third Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share a cornercorner with one MgO4 tetrahedra, corners with five AlO4 tetrahedra, edges with two AlO6 octahedra, and edges with four MgO6 octahedra. There are a spread of Al–O bond distances ranging from 1.80–2.05 Å. In the fourth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three MgO4 tetrahedra, corners with three AlO4 tetrahedra, edges with two equivalent MgO6 octahedra, and edges with four AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.87–2.04 Å. In the fifth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three equivalent MgO4 tetrahedra, corners with three equivalent AlO4 tetrahedra, edges with three MgO6 octahedra, and edges with three AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.87–2.03 Å. In the sixth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three MgO4 tetrahedra, corners with three AlO4 tetrahedra, edges with two equivalent MgO6 octahedra, and edges with four AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.87–2.04 Å. In the seventh Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three MgO4 tetrahedra, corners with three AlO4 tetrahedra, edges with two equivalent MgO6 octahedra, and edges with four AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.87–2.04 Å. In the eighth Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with five MgO6 octahedra and corners with seven AlO6 octahedra. The corner-sharing octahedra tilt angles range from 54–61°. There are a spread of Al–O bond distances ranging from 1.80–1.87 Å. In the ninth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three equivalent MgO4 tetrahedra, corners with three equivalent AlO4 tetrahedra, edges with two MgO6 octahedra, and edges with four AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.87–2.03 Å. In the tenth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three MgO4 tetrahedra, corners with three AlO4 tetrahedra, edges with two equivalent MgO6 octahedra, and edges with four AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.87–2.04 Å. In the eleventh Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three MgO4 tetrahedra, corners with three AlO4 tetrahedra, edges with two equivalent MgO6 octahedra, and edges with four AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.87–2.04 Å. In the twelfth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three equivalent MgO4 tetrahedra, corners with three equivalent AlO4 tetrahedra, edges with two MgO6 octahedra, and edges with four AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.87–2.03 Å. In the thirteenth Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with three MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 57–59°. There are a spread of Al–O bond distances ranging from 1.83–1.90 Å. In the fourteenth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three MgO4 tetrahedra, corners with three AlO4 tetrahedra, edges with two equivalent MgO6 octahedra, and edges with four AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.87–2.04 Å. In the fifteenth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three MgO4 tetrahedra, corners with three AlO4 tetrahedra, edges with two equivalent MgO6 octahedra, and edges with four AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.86–2.05 Å. In the sixteenth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three equivalent MgO4 tetrahedra, corners with three equivalent AlO4 tetrahedra, edges with two MgO6 octahedra, and edges with four AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.87–2.03 Å. In the seventeenth Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with three MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 57–59°. There are a spread of Al–O bond distances ranging from 1.83–1.91 Å. In the eighteenth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three MgO4 tetrahedra, corners with three AlO4 tetrahedra, edges with two equivalent MgO6 octahedra, and edges with four AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.86–2.05 Å. In the nineteenth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three MgO4 tetrahedra, corners with three AlO4 tetrahedra, edges with two equivalent MgO6 octahedra, and edges with four AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.86–2.05 Å. In the twentieth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three equivalent MgO4 tetrahedra, corners with three equivalent AlO4 tetrahedra, edges with two MgO6 octahedra, and edges with four AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.88–2.02 Å. In the twenty-first Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with three MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 57–59°. There are a spread of Al–O bond distances ranging from 1.83–1.90 Å. In the twenty-second Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three MgO4 tetrahedra, corners with three AlO4 tetrahedra, edges with two equivalent MgO6 octahedra, and edges with four AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.86–2.05 Å. In the twenty-third Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two equivalent MgO4 tetrahedra, corners with four AlO4 tetrahedra, edges with two equivalent MgO6 octahedra, and edges with four AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.85–2.00 Å. In the twenty-fourth Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with three MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 56–60°. There are a spread of Al–O bond distances ranging from 1.83–1.90 Å. In the twenty-fifth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three equivalent MgO4 tetrahedra, corners with three equivalent AlO4 tetrahedra, edges with two MgO6 octahedra, and edges with four AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.88–2.02 Å. In the twenty-sixth Al3+ site, Al3+ is bonded to six O2- atoms to

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on MgAl2O4 by Materials Project

MgAl2O4 is Spinel-like structured and crystallizes in the trigonal R3m space group. The structure is three-dimensional. there are ten inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with three equivalent MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 57–61°. There is three shorter (1.93 Å) and one longer (2.01 Å) Mg–O bond length. In the second Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with three equivalent MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 57–62°. There is three shorter (1.93 Å) and one longer (1.98 Å) Mg–O bond length. In the third Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with three equivalent MgO4 tetrahedra, corners with three equivalent AlO4 tetrahedra, and edges with six AlO6 octahedra. There are three shorter (2.00 Å) and three longer (2.10 Å) Mg–O bond lengths. In the fourth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 58–60°. There is one shorter (1.93 Å) and three longer (1.96 Å) Mg–O bond length. In the fifth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with three equivalent MgO4 tetrahedra, corners with three equivalent AlO4 tetrahedra, and edges with six AlO6 octahedra. There are three shorter (2.02 Å) and three longer (2.09 Å) Mg–O bond lengths. In the sixth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 59–60°. There is one shorter (1.95 Å) and three longer (1.97 Å) Mg–O bond length. In the seventh Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedral tilt angles are 59°. All Mg–O bond lengths are 1.96 Å. In the eighth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 58–62°. There is three shorter (1.97 Å) and one longer (2.00 Å) Mg–O bond length. In the ninth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 59–60°. There is three shorter (1.96 Å) and one longer (1.98 Å) Mg–O bond length. In the tenth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 59–62°. There is three shorter (1.96 Å) and one longer (2.01 Å) Mg–O bond length. There are ten inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with three MgO4 tetrahedra, corners with three AlO4 tetrahedra, edges with two MgO6 octahedra, and edges with four equivalent AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.88–2.04 Å. In the second Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share a cornercorner with one AlO4 tetrahedra, corners with five MgO4 tetrahedra, an edgeedge with one MgO6 octahedra, and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.88–2.07 Å. In the third Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.92–1.95 Å. In the fourth Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with three equivalent MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 55–60°. There is one shorter (1.84 Å) and three longer (1.85 Å) Al–O bond length. In the fifth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There is three shorter (1.92 Å) and three longer (1.95 Å) Al–O bond length. In the sixth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.93–1.95 Å. In the seventh Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There is three shorter (1.92 Å) and three longer (1.95 Å) Al–O bond length. In the eighth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two equivalent AlO4 tetrahedra, corners with four MgO4 tetrahedra, an edgeedge with one MgO6 octahedra, and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.92–1.99 Å. In the ninth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six MgO4 tetrahedra and edges with six AlO6 octahedra. There is three shorter (1.92 Å) and three longer (1.94 Å) Al–O bond length. In the tenth Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with three equivalent MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 55–61°. There is three shorter (1.83 Å) and one longer (1.86 Å) Al–O bond length. There are twenty inequivalent O2- sites. In the first O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+ and two equivalent Al3+ atoms. In the second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three equivalent Al3+ atoms. In the third O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three Al3+ atoms. In the fourth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+ and two equivalent Al3+ atoms. In the fifth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Al3+ atoms. In the sixth O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form distorted corner-sharing OMgAl3 trigonal pyramids. In the seventh O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 tetrahedra. In the eighth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 trigonal pyramids. In the ninth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Al3+ atoms. In the tenth O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 trigonal pyramids. In the eleventh O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 trigonal pyramids. In the twelfth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 trigonal pyramids. In the thirteenth O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 trigonal pyramids. In the fourteenth O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 trigonal pyramids. In the fifteenth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 trigonal pyramids. In the sixteenth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 trigonal pyramids. In the seventeenth O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 trigonal pyramids. In the eighteenth O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form a mixture of distorted corner and edge-sharing OMgAl3 tetrahedra. In the nineteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Al3+ atoms. In the twentieth O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form corner-sharing OMgAl3 tetrahedra.

36 MATERIALS SCIENCE↗