DOI: 10.17188/1728236
title: Materials Data on BaCa(Fe12O19)2 by Materials Project

description: BaCa(Fe12O19)2 crystallizes in the hexagonal P-6m2 space group. The structure is three-dimensional. Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with six equivalent BaO12 cuboctahedra, edges with six equivalent FeO6 octahedra, edges with three equivalent FeO5 trigonal bipyramids, and faces with six equivalent FeO6 octahedra. There are six shorter (2.91 Å) and six longer (3.01 Å) Ba–O bond lengths. Ca2+ is bonded to twelve O2- atoms to form distorted CaO12 cuboctahedra that share corners with six equivalent CaO12 cuboctahedra, edges with six equivalent FeO6 octahedra, edges with three equivalent FeO5 trigonal bipyramids, and faces with six equivalent FeO6 octahedra. There are six shorter (2.78 Å) and six longer (3.01 Å) Ca–O bond lengths. There are nine inequivalent Fe3+ sites. In the first Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with two equivalent FeO6 octahedra, corners with three FeO4 tetrahedra, a cornercorner with one FeO5 trigonal bipyramid, an edgeedge with one CaO12 cuboctahedra, and edges with five FeO6 octahedra. The corner-sharing octahedral tilt angles are 54°. There are a spread of Fe–O bond distances ranging from 1.96–2.14 Å. In the second Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with two equivalent FeO6 octahedra, corners with three FeO4 tetrahedra, a cornercorner with one FeO5 trigonal bipyramid, an edgeedge with one BaO12 cuboctahedra, and edges with five FeO6 octahedra. The corner-sharing octahedral tilt angles are 53°. There are a spread of Fe–O bond distances ranging from 1.96–2.14 Å. In the third Fe3+ site, Fe3+ is bonded to four O2- atoms to form corner-sharing FeO4 tetrahedra. The corner-sharing octahedra tilt angles range from 54–59°. All Fe–O bond lengths are 1.94 Å. In the fourth Fe3+ site, Fe3+ is bonded to four O2- atoms to form corner-sharing FeO4 tetrahedra. The corner-sharing octahedra tilt angles range from 54–59°. All Fe–O bond lengths are 1.94 Å. In the fifth Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six FeO4 tetrahedra and edges with six FeO6 octahedra. All Fe–O bond lengths are 2.04 Å. In the sixth Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six equivalent FeO6 octahedra, corners with three equivalent FeO5 trigonal bipyramids, faces with three equivalent BaO12 cuboctahedra, and a faceface with one FeO6 octahedra. The corner-sharing octahedral tilt angles are 53°. There are three shorter (2.02 Å) and three longer (2.10 Å) Fe–O bond lengths. In the seventh Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six equivalent FeO6 octahedra, corners with three equivalent FeO5 trigonal bipyramids, faces with three equivalent CaO12 cuboctahedra, and a faceface with one FeO6 octahedra. The corner-sharing octahedral tilt angles are 54°. There are three shorter (2.02 Å) and three longer (2.07 Å) Fe–O bond lengths. In the eighth Fe3+ site, Fe3+ is bonded to five O2- atoms to form FeO5 trigonal bipyramids that share corners with twelve FeO6 octahedra and edges with three equivalent BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 42–60°. There are three shorter (1.90 Å) and two longer (2.31 Å) Fe–O bond lengths. In the ninth Fe3+ site, Fe3+ is bonded to five O2- atoms to form FeO5 trigonal bipyramids that share corners with twelve FeO6 octahedra and edges with three equivalent CaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 41–61°. There are three shorter (1.90 Å) and two longer (2.25 Å) Fe–O bond lengths. There are ten inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to one Ba2+ and three Fe3+ atoms. In the second O2- site, O2- is bonded in a 4-coordinate geometry to one Ca2+ and three Fe3+ atoms. In the third O2- site, O2- is bonded to four Fe3+ atoms to form distorted corner-sharing OFe4 tetrahedra. In the fourth O2- site, O2- is bonded to four Fe3+ atoms to form distorted corner-sharing OFe4 tetrahedra. In the fifth O2- site, O2- is bonded in a 5-coordinate geometry to two equivalent Ba2+ and three Fe3+ atoms. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Ca2+ and three Fe3+ atoms. In the seventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Fe3+ atoms. In the eighth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Fe3+ atoms. In the ninth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Fe3+ atoms. In the tenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Fe3+ atoms.