DOI: 10.17188/1263352
title: Materials Data on MgAl2O4 by Materials Project

description: 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 three equivalent MgO6 octahedra and corners with nine AlO6 octahedra. The corner-sharing octahedra tilt angles range from 57–62°. There is three shorter (1.94 Å) and one longer (2.02 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 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 2.00–2.11 Å. In the fourth 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 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 59–60°. There are a spread of Mg–O bond distances ranging from 1.95–1.97 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 55–62°. There are a spread of Mg–O bond distances ranging from 1.94–2.00 Å. In the seventh 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 1.94–1.97 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 59–61°. There is one shorter (1.95 Å) and three longer (1.97 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 58–60°. There are a spread of Mg–O bond distances ranging from 1.95–1.98 Å. 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 59–61°. There is one shorter (1.95 Å) and three longer (1.97 Å) Mg–O bond length. 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 one shorter (1.95 Å) and three longer (1.97 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 58–60°. There are a spread of Mg–O bond distances ranging from 1.95–1.98 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 58–60°. There is three shorter (1.96 Å) and one longer (1.98 Å) Mg–O bond length. 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 59–62°. There is three shorter (1.96 Å) and one longer (2.01 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 two equivalent MgO6 octahedra and corners with ten AlO6 octahedra. The corner-sharing octahedra tilt angles range from 52–62°. There are a spread of Al–O bond distances ranging from 1.81–1.85 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, an edgeedge with one MgO6 octahedra, and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.88–2.06 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, 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 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 1.88–2.06 Å. In the fifth 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 1.88–2.08 Å. In the sixth 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 1.91–2.00 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 are a spread of Al–O bond distances ranging from 1.93–1.95 Å. 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 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 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 are a spread of Al–O bond distances ranging from 1.93–1.95 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 is three shorter (1.92 Å) and three longer (1.95 Å) Al–O bond length. 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 1.93–1.95 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 1.93–1.95 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 is three shorter (1.92 Å) and three longer (1.95 Å) Al–O bond length. In the sixteenth 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 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 1.93–1.95 Å. In the eighteenth 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 nineteenth 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 twentieth 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 twenty-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°. There is three shorter (1.82 Å) and one longer (1.83 Å) Al–O bond length. 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 in a 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 one Mg2+ and three Al3+ atoms. In the sixth O2- site, O2- is bonded to one Mg2+ and three Al3+ atoms to form corner-sharing OMgAl3 tetrahedra. 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 three OMg2Al2 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 to two Mg2+ and two Al3+ atoms to form distorted OMg2Al2 trigonal pyramids that share corners with four OMgAl3 tetrahedra, corners with three OMgAl3 trigonal pyramids, and edges with two OMg2Al2 trigonal pyramids. 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 to two Mg2+ and two equivalent Al3+ atoms to form distorted OMg2Al2 trigonal pyramids that share corners with four OMgAl3 tetrahedra, corners with three OMgAl3 trigonal pyramids, and edges with two equivalent OMg2Al2 trigonal pyramids. In the thirteenth 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 fourteenth O2- site, O2- is bonded in a rectangular see-saw-like geometr