Materials Data on Mg6AlBiO8 by Materials Project

Abstract

Mg6AlBiO8 is Caswellsilverite-derived structured and crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. there are three 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 AlO6 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 (2.07 Å) and four longer (2.28 Å) Mg–O bond lengths. In the second Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with two equivalent BiO6 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 (2.02 Å) and four longer (2.28 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 six equivalent MgO6 octahedra, edges with two equivalent AlO6 octahedra, edges with two equivalent BiO6 octahedra, and edges with eight MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. There are a spread of Mg–O bond distances ranging from 2.07–2.37 Å. Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two equivalent MgO6 octahedra, corners with four equivalent AlO6 octahedra, edges with four equivalent BiO6 octahedra, and edges with eight equivalent MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (2.28 Å) and two longer (2.38 Å) Al–O bond lengths. Bi1+ is bonded to six O2- atoms to form BiO6 octahedra that share corners with two equivalent MgO6 octahedra, corners with four equivalent BiO6 octahedra, edges with four equivalent AlO6 octahedra, and edges with eight equivalent MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (2.28 Å) and two longer (2.43 Å) Bi–O bond lengths. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded to five Mg2+ and one Al3+ atom to form OMg5Al octahedra that share corners with six equivalent OMg5Al octahedra and edges with twelve OMg5Bi octahedra. The corner-sharing octahedral tilt angles are 0°. In the second O2- site, O2- is bonded to five Mg2+ and one Bi1+ atom to form OMg5Bi octahedra that share corners with six equivalent OMg5Bi octahedra and edges with twelve OMg5Al octahedra. The corner-sharing octahedra tilt angles range from 0–3°. In the third O2- site, O2- is bonded to two equivalent Mg2+, two equivalent Al3+, and two equivalent Bi1+ atoms to form OMg2Al2Bi2 octahedra that share corners with six OMg2Al2Bi2 octahedra and edges with twelve OMg5Al octahedra. The corner-sharing octahedral tilt angles are 0°. In the fourth O2- site, O2- is bonded to six Mg2+ atoms to form OMg6 octahedra that share corners with six OMg2Al2Bi2 octahedra and edges with twelve OMg5Al octahedra. The corner-sharing octahedral tilt angles are 0°. In the fifth O2- site, O2- is bonded to two equivalent Mg2+, two equivalent Al3+, and two equivalent Bi1+ atoms to form OMg2Al2Bi2 octahedra that share corners with six OMg6 octahedra and edges with twelve OMg5Al octahedra. The corner-sharing octahedral tilt angles are 0°. Both O–Mg bond lengths are 2.37 Å.