Materials Data on Ba8Ca3Nb5O24 by Materials Project

Abstract

Ba8Ca3Nb5O24 is (Cubic) Perovskite-derived structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Ba is bonded to twelve O atoms to form BaO12 cuboctahedra that share corners with twelve equivalent BaO12 cuboctahedra, faces with six equivalent BaO12 cuboctahedra, faces with three CaO6 octahedra, and faces with five NbO6 octahedra. There are a spread of Ba–O bond distances ranging from 2.90–3.16 Å. There are three inequivalent Ca sites. In the first Ca site, Ca is bonded to six O atoms to form CaO6 octahedra that share corners with six NbO6 octahedra and faces with eight equivalent BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–10°. There are four shorter (2.28 Å) and two longer (2.32 Å) Ca–O bond lengths. In the second Ca site, Ca is bonded to six O atoms to form CaO6 octahedra that share corners with six NbO6 octahedra and faces with eight equivalent BaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (2.28 Å) and two longer (2.31 Å) Ca–O bond lengths. In the third Ca site, Ca is bonded to six O atoms to form CaO6 octahedra that share corners with six NbO6 octahedra and faces with eight equivalent BaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (2.28 Å) and two longer (2.31 Å) Ca–O bond lengths. There are three inequivalent Nb sites. In the first Nb site, Nb is bonded to six O atoms to form distorted NbO6 octahedra that share a cornercorner with one NbO6 octahedra, corners with five CaO6 octahedra, and faces with eight equivalent BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–10°. There are a spread of Nb–O bond distances ranging from 1.91–2.42 Å. In the second Nb site, Nb is bonded to six O atoms to form NbO6 octahedra that share corners with two equivalent NbO6 octahedra, corners with four CaO6 octahedra, and faces with eight equivalent BaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Nb–O bond distances ranging from 1.97–2.17 Å. In the third Nb site, Nb is bonded to six O atoms to form NbO6 octahedra that share corners with six NbO6 octahedra and faces with eight equivalent BaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (1.99 Å) and four longer (2.08 Å) Nb–O bond lengths. There are six inequivalent O sites. In the first O site, O is bonded in a 2-coordinate geometry to four equivalent Ba, one Ca, and one Nb atom. In the second O site, O is bonded in a distorted linear geometry to four equivalent Ba, one Ca, and one Nb atom. In the third O site, O is bonded in a distorted linear geometry to four equivalent Ba and two Nb atoms. In the fourth O site, O is bonded in a distorted linear geometry to four equivalent Ba, one Ca, and one Nb atom. In the fifth O site, O is bonded in a distorted linear geometry to four equivalent Ba, one Ca, and one Nb atom. In the sixth O site, O is bonded to four equivalent Ba and two Nb atoms to form distorted corner-sharing OBa4Nb2 octahedra. The corner-sharing octahedral tilt angles are 0°.