Materials Data on BaNb2Bi2O9 by Materials Project
BaBi2Nb2O9 crystallizes in the orthorhombic Cmc2_1 space group. The structure is three-dimensional. Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with four equivalent BaO12 cuboctahedra, faces with four equivalent BaO12 cuboctahedra, and faces with eight equivalent NbO6 octahedra. There are a spread of Ba–O bond distances ranging from 2.77–2.99 Å. Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with five equivalent NbO6 octahedra and faces with four equivalent BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 8–16°. There are a spread of Nb–O bond distances ranging from 1.91–2.19 Å. Bi3+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Bi–O bond distances ranging from 2.18–2.80 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a 6-coordinate geometry to four equivalent Ba2+ and two equivalent Nb5+ atoms. In the second O2- site, O2- is bonded in a 4-coordinate geometry to four equivalent Bi3+ atoms. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ba2+ and two equivalent Nb5+ atoms. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to one Nb5+ and two equivalent Bi3+ atoms. In the fifth O2- site, O2- is bonded in a distorted linear geometry to two equivalent Ba2+ and two equivalent Nb5+ atoms.