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DOE OSTI2020

Materials Data on MgAlBO4 by Materials Project

MgAlBO4 is Ilmenite-derived structured and crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with four equivalent MgO6 octahedra, corners with four equivalent AlO6 octahedra, corners with four equivalent BO4 tetrahedra, edges with two equivalent AlO6 octahedra, and an edgeedge with one BO4 tetrahedra. The corner-sharing octahedra tilt angles range from 55–62°. There are a spread of Mg–O bond distances ranging from 2.06–2.23 Å. Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with four equivalent MgO6 octahedra, corners with two equivalent BO4 tetrahedra, edges with two equivalent MgO6 octahedra, edges with two equivalent AlO6 octahedra, and edges with two equivalent BO4 tetrahedra. The corner-sharing octahedra tilt angles range from 55–62°. There are a spread of Al–O bond distances ranging from 1.87–2.00 Å. B3+ is bonded to four O2- atoms to form BO4 tetrahedra that share corners with two equivalent AlO6 octahedra, corners with four equivalent MgO6 octahedra, an edgeedge with one MgO6 octahedra, and edges with two equivalent AlO6 octahedra. The corner-sharing octahedra tilt angles range from 53–64°. There are a spread of B–O bond distances ranging from 1.45–1.59 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two equivalent Mg2+, one Al3+, and one B3+ atom. In the second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+, two equivalent Al3+, and one B3+ atom. In the third O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+, two equivalent Al3+, and one B3+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg30AlBO32 by Materials Project

Mg30AlBO32 crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. there are eight inequivalent Mg sites. In the first Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with two equivalent AlO6 octahedra, corners with four MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Mg–O bond distances ranging from 2.09–2.23 Å. In the second Mg site, Mg is bonded to six O atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Mg–O bond distances ranging from 2.02–2.17 Å. In the third Mg site, Mg is bonded to six O atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.12 Å) and four longer (2.14 Å) Mg–O bond lengths. In the fourth Mg site, Mg is bonded to six O atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (2.11 Å) and two longer (2.14 Å) Mg–O bond lengths. In the fifth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, an edgeedge with one AlO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 1–16°. There are a spread of Mg–O bond distances ranging from 2.11–2.16 Å. In the sixth Mg site, Mg is bonded to six O atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedra tilt angles range from 1–3°. There are a spread of Mg–O bond distances ranging from 2.12–2.14 Å. In the seventh Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, an edgeedge with one AlO6 octahedra, and edges with eleven MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–5°. All Mg–O bond lengths are 2.13 Å. In the eighth Mg site, Mg is bonded to six O atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–7°. There are a spread of Mg–O bond distances ranging from 2.11–2.14 Å. Al is bonded to six O atoms to form AlO6 octahedra that share corners with four equivalent MgO6 octahedra and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There is two shorter (1.87 Å) and four longer (2.03 Å) Al–O bond length. B is bonded in a distorted square co-planar geometry to four equivalent O atoms. All B–O bond lengths are 2.23 Å. There are fourteen inequivalent O sites. In the first O site, O is bonded to five Mg and one Al atom to form OMg5Al octahedra that share corners with four OMg5Al octahedra, corners with two equivalent OMg5B square pyramids, edges with ten OMg6 octahedra, and edges with two equivalent OMg4Al square pyramids. The corner-sharing octahedra tilt angles range from 0–3°. There are two shorter (2.16 Å) and one longer (2.23 Å) O–Mg bond lengths. In the second O site, O is bonded to five Mg and one B atom to form distorted OMg5B square pyramids that share corners with four OMg5Al octahedra, corners with four OMg4Al square pyramids, edges with eight OMg6 octahedra, and edges with two equivalent OMg5B square pyramids. The corner-sharing octahedra tilt angles range from 1–4°. In the third O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OMg5Al octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. Both O–Mg bond lengths are 2.14 Å. In the fourth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with four OMg6 octahedra, corners with two equivalent OMg5B square pyramids, edges with ten OMg6 octahedra, and edges with two equivalent OMg5B square pyramids. The corner-sharing octahedral tilt angles are 0°. In the fifth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OMg5Al octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. There are two shorter (2.13 Å) and two longer (2.14 Å) O–Mg bond lengths. In the sixth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with four OMg6 octahedra, corners with two equivalent OMg5B square pyramids, edges with ten OMg6 octahedra, and edges with two equivalent OMg5B square pyramids. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.12 Å) and two longer (2.14 Å) O–Mg bond lengths. In the seventh O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six equivalent OMg6 octahedra, edges with nine OMg5Al octahedra, and edges with three OMg5B square pyramids. The corner-sharing octahedra tilt angles range from 1–2°. In the eighth O site, O is bonded to four equivalent Mg and one Al atom to form OMg4Al square pyramids that share corners with four equivalent OMg6 octahedra, corners with five OMg4Al square pyramids, and edges with eight OMg5Al octahedra. The corner-sharing octahedral tilt angles are 10°. In the ninth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with four OMg6 octahedra, corners with two equivalent OMg4Al square pyramids, edges with ten OMg6 octahedra, and edges with two equivalent OMg5B square pyramids. The corner-sharing octahedra tilt angles range from 0–2°. In the tenth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with four OMg6 octahedra, corners with two equivalent OMg4Al square pyramids, edges with ten OMg6 octahedra, and edges with two equivalent OMg5B square pyramids. The corner-sharing octahedra tilt angles range from 0–2°. There are two shorter (2.12 Å) and two longer (2.14 Å) O–Mg bond lengths. In the eleventh O site, O is bonded to six Mg atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. In the twelfth O site, O is bonded to five Mg and one Al atom to form OMg5Al octahedra that share corners with four OMg5Al octahedra, corners with two equivalent OMg5B square pyramids, edges with ten OMg5Al octahedra, and edges with two equivalent OMg4Al square pyramids. The corner-sharing octahedra tilt angles range from 0–3°. In the thirteenth O site, O is bonded to six Mg atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. The O–Mg bond length is 2.11 Å. In the fourteenth O site, O is bonded to six Mg atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. There are a spread of O–Mg bond distances ranging from 2.11–2.14 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg30AlBO32 by Materials Project

Mg30AlBO32 is Molybdenum Carbide MAX Phase-derived structured and crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. there are eight inequivalent Mg sites. In the first Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with two equivalent MgO6 octahedra, corners with two equivalent AlO6 octahedra, corners with two equivalent BO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Mg–O bond distances ranging from 1.99–2.28 Å. In the second Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with two equivalent AlO6 octahedra, corners with four equivalent MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (2.10 Å) and two longer (2.25 Å) Mg–O bond lengths. In the third Mg site, Mg is bonded to six O atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Mg–O bond distances ranging from 2.11–2.16 Å. In the fourth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with two equivalent BO6 octahedra, corners with four equivalent MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.01 Å) and four longer (2.15 Å) Mg–O bond lengths. In the fifth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, an edgeedge with one AlO6 octahedra, an edgeedge with one BO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 2–10°. There are a spread of Mg–O bond distances ranging from 2.10–2.17 Å. In the sixth Mg site, Mg is bonded to six O atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedral tilt angles are 2°. There are a spread of Mg–O bond distances ranging from 2.12–2.14 Å. In the seventh Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, an edgeedge with one AlO6 octahedra, and edges with eleven MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–9°. There are a spread of Mg–O bond distances ranging from 2.11–2.15 Å. In the eighth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, an edgeedge with one BO6 octahedra, and edges with eleven MgO6 octahedra. The corner-sharing octahedra tilt angles range from 1–9°. There are a spread of Mg–O bond distances ranging from 2.11–2.16 Å. Al is bonded to six O atoms to form AlO6 octahedra that share corners with six MgO6 octahedra and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There is four shorter (1.98 Å) and two longer (2.01 Å) Al–O bond length. B is bonded to six O atoms to form distorted BO6 octahedra that share corners with six MgO6 octahedra and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.25 Å) and four longer (2.27 Å) B–O bond lengths. There are sixteen inequivalent O sites. In the first O site, O is bonded to five Mg and one Al atom to form OMg5Al octahedra that share corners with six OMg5Al octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. In the second O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with four OMg5Al octahedra, corners with two equivalent OMg5B square pyramids, edges with ten OMg6 octahedra, and edges with two OMg5B square pyramids. The corner-sharing octahedra tilt angles range from 0–3°. In the third O site, O is bonded to five Mg and one B atom to form distorted OMg5B square pyramids that share corners with four equivalent OMg6 octahedra, corners with two equivalent OMg5B square pyramids, edges with eight OMg6 octahedra, and edges with four OMg5B square pyramids. The corner-sharing octahedral tilt angles are 4°. In the fourth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six equivalent OMg6 octahedra, edges with nine OMg5Al octahedra, and edges with three OMg5B square pyramids. The corner-sharing octahedra tilt angles range from 1–3°. In the fifth O site, O is bonded to five Mg and one Al atom to form OMg5Al octahedra that share corners with four OMg5Al octahedra, corners with two equivalent OMg5B square pyramids, edges with ten OMg5Al octahedra, and edges with two OMg5B square pyramids. The corner-sharing octahedra tilt angles range from 0–6°. In the sixth O site, O is bonded to five Mg and one B atom to form distorted OMg5B square pyramids that share corners with four OMg5Al octahedra, corners with two equivalent OMg5B square pyramids, edges with eight OMg6 octahedra, and edges with four OMg5B square pyramids. The corner-sharing octahedra tilt angles range from 6–10°. The O–Mg bond length is 1.99 Å. In the seventh O site, O is bonded to five Mg and one B atom to form distorted OMg5B square pyramids that share corners with four OMg5Al octahedra, corners with two equivalent OMg5B square pyramids, edges with eight OMg6 octahedra, and edges with four OMg5B square pyramids. The corner-sharing octahedra tilt angles range from 6–10°. There are a spread of O–Mg bond distances ranging from 1.99–2.12 Å. In the eighth O site, O is bonded to six Mg atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–6°. In the ninth O site, O is bonded to six Mg atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–6°. There are two shorter (2.13 Å) and two longer (2.14 Å) O–Mg bond lengths. In the tenth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with four OMg6 octahedra, corners with two equivalent OMg5B square pyramids, edges with ten OMg6 octahedra, and edges with two equivalent OMg5B square pyramids. The corner-sharing octahedra tilt angles range from 0–2°. The O–Mg bond length is 2.11 Å. In the eleventh O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with four OMg6 octahedra, corners with two equivalent OMg5B square pyramids, edges with ten OMg6 octahedra, and edges with two equivalent OMg5B square pyramids. The corner-sharing octahedra tilt angles range from 0–2°. There are two shorter (2.12 Å) and two longer (2.15 Å) O–Mg bond lengths. In the twelfth O site, O is bonded to five Mg and one B atom to form distorted OMg5B square pyramids that share corners with four OMg5Al octahedra, corners with two equivalent OMg5B square pyramids, edges with eight OMg6 octahedra, and edges with four OMg5B square pyramids. The corner-sharing octahedra tilt angles range from 6–10°. Both O–Mg bond lengths are 2.12 Å. In the thirteenth O site, O is bonded to five Mg and one B atom to form distorted OMg5B square pyramids that share corners with four OMg5Al octahedra, corners with two equivalent OMg5B square pyramids, edges with eight OMg6 octahedra, and edges with four OMg5B square pyramids. The corner-sharing octahedra tilt angles range from 6–10°. There are two shorter (2.10 Å) and two longer (2.12 Å) O–Mg bond lengths. In the fourteenth O site, O is bonded to six Mg atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–6°. There are two shorter (2.13 Å) and one longer (2.16 Å) O–Mg bond lengths. In the fifteenth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with four OMg6 octahedra, corners with two equivalent OMg5B square pyramids, edges with ten OMg6 octahedra, and edges with two equivalent OMg5B square pyramids. The corner-sharing octahedra tilt angles range from 0–2°. Both O–Mg bond lengths are 2.15 Å. In the sixteenth O site, O is bonded to six Mg atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–6°. There are a spread of O–Mg bond distances ranging from 2.13–2.16 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg14AlBO16 by Materials Project

Mg14AlBO16 crystallizes in the orthorhombic Pmmm space group. The structure is three-dimensional. there are eight inequivalent Mg sites. In the first Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with two equivalent AlO6 octahedra, corners with four MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Mg–O bond distances ranging from 2.09–2.25 Å. In the second Mg site, Mg is bonded to six O atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Mg–O bond distances ranging from 2.01–2.19 Å. In the third Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with two equivalent AlO6 octahedra, and edges with eight MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–18°. There are a spread of Mg–O bond distances ranging from 2.09–2.19 Å. In the fourth Mg site, Mg is bonded to six O atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. There are a spread of Mg–O bond distances ranging from 2.12–2.16 Å. In the fifth Mg site, Mg is bonded to six O atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. There are a spread of Mg–O bond distances ranging from 2.12–2.16 Å. In the sixth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with two equivalent AlO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–6°. There are two shorter (2.12 Å) and four longer (2.13 Å) Mg–O bond lengths. In the seventh Mg site, Mg is bonded to six O atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–8°. There are a spread of Mg–O bond distances ranging from 2.10–2.16 Å. In the eighth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six equivalent MgO6 octahedra, an edgeedge with one AlO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 3–18°. There are a spread of Mg–O bond distances ranging from 2.10–2.19 Å. Al is bonded to six O atoms to form AlO6 octahedra that share corners with two equivalent MgO6 octahedra, corners with two equivalent AlO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Al–O bond distances ranging from 1.85–2.12 Å. B is bonded in a distorted square co-planar geometry to four O atoms. There are two shorter (2.12 Å) and two longer (2.24 Å) B–O bond lengths. There are nine inequivalent O sites. In the first O site, O is bonded to five Mg and one Al atom to form OMg5Al octahedra that share corners with four equivalent OMg5Al octahedra, corners with two equivalent OMg5B square pyramids, edges with ten OMg6 octahedra, and edges with two equivalent OMg4Al square pyramids. The corner-sharing octahedra tilt angles range from 0–6°. In the second O site, O is bonded to five Mg and one B atom to form distorted OMg5B square pyramids that share corners with two equivalent OMg5Al octahedra, corners with six OMg5B square pyramids, and edges with ten OMg4B2 octahedra. The corner-sharing octahedral tilt angles are 1°. In the third O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six equivalent OMg6 octahedra, edges with eight OMg5Al octahedra, and edges with four OMg5B square pyramids. The corner-sharing octahedra tilt angles range from 1–3°. In the fourth O site, O is bonded to four Mg and two equivalent Al atoms to form OMg4Al2 octahedra that share corners with six OMg4Al2 octahedra, edges with eight OMg5Al octahedra, and edges with four equivalent OMg4Al square pyramids. The corner-sharing octahedral tilt angles are 0°. In the fifth O site, O is bonded to four Mg and two equivalent B atoms to form OMg4B2 octahedra that share corners with six OMg4Al2 octahedra, corners with four equivalent OMg4Al square pyramids, edges with four equivalent OMg6 octahedra, and edges with four equivalent OMg5B square pyramids. The corner-sharing octahedral tilt angles are 0°. In the sixth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OMg4Al2 octahedra and edges with twelve OMg5Al octahedra. The corner-sharing octahedral tilt angles are 0°. In the seventh O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OMg4B2 octahedra, edges with eight OMg6 octahedra, and edges with four equivalent OMg5B square pyramids. The corner-sharing octahedral tilt angles are 0°. In the eighth O site, O is bonded to four Mg and one Al atom to form OMg4Al square pyramids that share corners with four OMg6 octahedra, corners with five OMg5B square pyramids, and edges with eight OMg5Al octahedra. The corner-sharing octahedra tilt angles range from 12–81°. In the ninth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with four equivalent OMg6 octahedra, corners with two equivalent OMg4Al square pyramids, edges with ten OMg5Al octahedra, and edges with two equivalent OMg5B square pyramids. The corner-sharing octahedra tilt angles range from 0–4°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg14AlBO16 by Materials Project

Mg14AlBO16 crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. there are seven inequivalent Mg sites. In the first Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with two equivalent MgO6 octahedra, corners with two equivalent AlO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Mg–O bond distances ranging from 1.97–2.32 Å. In the second Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with two equivalent AlO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–11°. There are a spread of Mg–O bond distances ranging from 2.11–2.15 Å. In the third Mg site, Mg is bonded to six O atoms to form a mixture of corner and edge-sharing MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–12°. There are a spread of Mg–O bond distances ranging from 2.08–2.18 Å. In the fourth Mg site, Mg is bonded to six O atoms to form a mixture of corner and edge-sharing MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–12°. There are a spread of Mg–O bond distances ranging from 2.08–2.18 Å. In the fifth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with two equivalent AlO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–11°. There are a spread of Mg–O bond distances ranging from 2.11–2.15 Å. In the sixth Mg site, Mg is bonded to six O atoms to form a mixture of corner and edge-sharing MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–12°. There are a spread of Mg–O bond distances ranging from 2.08–2.18 Å. In the seventh Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six equivalent MgO6 octahedra, an edgeedge with one AlO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 4–12°. There are a spread of Mg–O bond distances ranging from 2.09–2.20 Å. Al is bonded to six O atoms to form AlO6 octahedra that share corners with two equivalent AlO6 octahedra, corners with four equivalent MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (1.95 Å) and two longer (2.12 Å) Al–O bond lengths. B is bonded in a distorted linear geometry to two equivalent O atoms. Both B–O bond lengths are 2.12 Å. There are six inequivalent O sites. In the first O site, O is bonded to five Mg and one Al atom to form OMg5Al octahedra that share corners with four equivalent OMg5Al octahedra, corners with two equivalent OMg5 square pyramids, edges with ten OMg5Al octahedra, and edges with two equivalent OMg5 square pyramids. The corner-sharing octahedra tilt angles range from 0–11°. In the second O site, O is bonded to five Mg atoms to form distorted OMg5 square pyramids that share corners with four OMg5Al octahedra, corners with five equivalent OMg5 square pyramids, and edges with eight OMg5Al octahedra. The corner-sharing octahedra tilt angles range from 12–84°. In the third O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six equivalent OMg6 octahedra, edges with eight OMg5Al octahedra, and edges with four equivalent OMg5 square pyramids. The corner-sharing octahedra tilt angles range from 1–4°. In the fourth O site, O is bonded to four Mg and two equivalent Al atoms to form OMg4Al2 octahedra that share corners with six OMg4Al2 octahedra and edges with twelve OMg5Al octahedra. The corner-sharing octahedral tilt angles are 0°. In the fifth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OMg4Al2 octahedra, edges with eight OMg5Al octahedra, and edges with four equivalent OMg5 square pyramids. The corner-sharing octahedral tilt angles are 0°. In the sixth O site, O is bonded to four Mg and two equivalent B atoms to form OMg4B2 octahedra that share corners with six OMg4B2 octahedra, corners with eight equivalent OMg5 square pyramids, and edges with four equivalent OMg6 octahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗