DOI: 10.17188/1741398
title: Materials Data on BaCaMg14O16 by Materials Project

description: BaCaMg14O16 is Caswellsilverite-derived structured and crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. Ba2+ is bonded to six O2- atoms to form BaO6 octahedra that share corners with two equivalent BaO6 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 (2.27 Å) and four longer (2.46 Å) Ba–O bond lengths. Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with two equivalent CaO6 octahedra, corners with four equivalent MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. All Ca–O bond lengths are 2.27 Å. There are six 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 BaO6 octahedra, corners with two equivalent CaO6 octahedra, corners with two equivalent 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 1.94–2.27 Å. In the second Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with two equivalent CaO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. There are a spread of Mg–O bond distances ranging from 2.16–2.27 Å. In the third Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with two equivalent CaO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. There are a spread of Mg–O bond distances ranging from 2.16–2.27 Å. In the fourth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with two equivalent BaO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–7°. There are a spread of Mg–O bond distances ranging from 2.08–2.32 Å. In the fifth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with two equivalent BaO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–7°. There are a spread of Mg–O bond distances ranging from 2.08–2.32 Å. In the sixth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six equivalent MgO6 octahedra, an edgeedge with one BaO6 octahedra, an edgeedge with one CaO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 3–11°. There are a spread of Mg–O bond distances ranging from 2.16–2.27 Å. There are ten inequivalent O2- sites. In the first O2- site, O2- is bonded to one Ca2+ and five Mg2+ atoms to form a mixture of edge and corner-sharing OCaMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. In the second O2- site, O2- is bonded to one Ba2+ and five Mg2+ atoms to form a mixture of edge and corner-sharing OBaMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–7°. Both O–Mg bond lengths are 2.27 Å. In the third O2- site, O2- is bonded to one Ba2+ and five Mg2+ atoms to form a mixture of edge and corner-sharing OBaMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–7°. There are two shorter (2.25 Å) and two longer (2.27 Å) O–Mg bond lengths. In the fourth O2- site, O2- is bonded to six Mg2+ atoms to form OMg6 octahedra that share corners with six equivalent OMg6 octahedra and edges with twelve OCaMg5 octahedra. The corner-sharing octahedra tilt angles range from 2–6°. In the fifth O2- site, O2- is bonded to two equivalent Ca2+ and four Mg2+ atoms to form OCa2Mg4 octahedra that share corners with six OCa2Mg4 octahedra and edges with twelve OCaMg5 octahedra. The corner-sharing octahedral tilt angles are 0°. In the sixth O2- site, O2- is bonded to six Mg2+ atoms to form OMg6 octahedra that share corners with six OCa2Mg4 octahedra and edges with twelve OCaMg5 octahedra. The corner-sharing octahedral tilt angles are 0°. In the seventh O2- site, O2- is bonded to two equivalent Ba2+ and four Mg2+ atoms to form OBa2Mg4 octahedra that share corners with six OMg6 octahedra and edges with twelve OBaMg5 octahedra. The corner-sharing octahedral tilt angles are 0°. In the eighth O2- site, O2- is bonded to one Ca2+ and five Mg2+ atoms to form a mixture of edge and corner-sharing OCaMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. Both O–Mg bond lengths are 2.16 Å. In the ninth O2- site, O2- is bonded to one Ba2+ and five Mg2+ atoms to form a mixture of edge and corner-sharing OBaMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–7°. The O–Mg bond length is 1.94 Å. In the tenth O2- site, O2- is bonded to one Ba2+ and five Mg2+ atoms to form a mixture of edge and corner-sharing OBaMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–7°. There are one shorter (1.94 Å) and two longer (2.25 Å) O–Mg bond lengths.