Materials Data on Ba2Fe3O8 by Materials Project

Ba2Fe3O8 crystallizes in the tetragonal P4/mmm space group. The structure is two-dimensional and consists of one Ba2Fe3O8 sheet oriented in the (0, 0, 1) direction. Ba is bonded to twelve O atoms to form BaO12 cuboctahedra that share corners with eight equivalent BaO12 cuboctahedra, faces with five equivalent BaO12 cuboctahedra, faces with four equivalent FeO6 octahedra, and faces with four equivalent FeO5 square pyramids. There are a spread of Ba–O bond distances ranging from 2.77–2.89 Å. There are two inequivalent Fe sites. In the first Fe site, Fe is bonded to five O atoms to form FeO5 square pyramids that share a cornercorner with one FeO6 octahedra, corners with four equivalent FeO5 square pyramids, and faces with four equivalent BaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. There is four shorter (1.97 Å) and one longer (1.98 Å) Fe–O bond length. In the second Fe site, Fe is bonded to six O atoms to form FeO6 octahedra that share corners with four equivalent FeO6 octahedra, corners with two equivalent FeO5 square pyramids, and faces with eight equivalent BaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (1.96 Å) and two longer (2.09 Å) Fe–O bond lengths. There are three inequivalent O sites. In the first O site, O is bonded in a distorted linear geometry to two equivalent Ba and two equivalent Fe atoms. In the second O site, O is bonded in a distorted linear geometry to four equivalent Ba and two equivalent Fe atoms. In the third O site, O is bonded to four equivalent Ba and two Fe atoms to form a mixture of distorted edge and corner-sharing OBa4Fe2 octahedra. The corner-sharing octahedral tilt angles are 0°.