Materials Data on MgBeAl4O8 by Materials Project

Abstract

MgBeAl4O8 is Spinel-derived structured and crystallizes in the hexagonal P6_3mc 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 twelve AlO6 octahedra. The corner-sharing octahedra tilt angles range from 58–59°. All Mg–O bond lengths are 1.91 Å. 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 59–60°. All Mg–O bond lengths are 1.91 Å. There are two inequivalent Be2+ sites. In the first Be2+ site, Be2+ is bonded to four O2- atoms to form BeO4 tetrahedra that share corners with twelve AlO6 octahedra. The corner-sharing octahedral tilt angles are 57°. There is one shorter (1.77 Å) and three longer (1.81 Å) Be–O bond length. In the second Be2+ site, Be2+ is bonded to four O2- atoms to form BeO4 tetrahedra that share corners with six AlO6 octahedra and edges with three equivalent AlO6 octahedra. The corner-sharing octahedra tilt angles range from 58–60°. There is one shorter (1.61 Å) and three longer (1.71 Å) Be–O bond length. There are four 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 BeO4 tetrahedra, and edges with six AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.88–1.98 Å. In the second Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two equivalent AlO6 octahedra, a cornercorner with one BeO4 tetrahedra, corners with three MgO4 tetrahedra, edges with five AlO6 octahedra, and an edgeedge with one BeO4 tetrahedra. The corner-sharing octahedral tilt angles are 54°. There are a spread of Al–O bond distances ranging from 1.89–1.97 Å. In the third Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six equivalent AlO6 octahedra, corners with three equivalent MgO4 tetrahedra, corners with three equivalent BeO4 tetrahedra, and edges with three equivalent AlO6 octahedra. The corner-sharing octahedral tilt angles are 54°. There is three shorter (1.95 Å) and three longer (2.03 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 three equivalent MgO4 tetrahedra, corners with three equivalent BeO4 tetrahedra, and edges with six AlO6 octahedra. There is three shorter (1.89 Å) and three longer (1.97 Å) Al–O bond length. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Be2+ and three Al3+ atoms. In the second O2- site, O2- is bonded to one Be2+ and three equivalent Al3+ atoms to form distorted corner-sharing OBeAl3 tetrahedra. In the third O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Be2+ and three Al3+ atoms. 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 Al3+ atoms to form distorted OMgAl3 tetrahedra that share corners with four OBeAl3 tetrahedra, a cornercorner with one OMgAl3 trigonal pyramid, edges with two equivalent OMgAl3 tetrahedra, and an edgeedge with one OMgAl3 trigonal pyramid. In the seventh O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Be2+ and three equivalent Al3+ atoms. In the eighth O2- site, O2- is bonded to one Mg2+ and three equivalent Al3+ atoms to form distorted OMgAl3 trigonal pyramids that share corners with three equivalent OBeAl3 tetrahedra, corners with three equivalent OMgAl3 trigonal pyramids, and edges with three equivalent OMgAl3 tetrahedra.