Materials Data on BaV4O9 by Materials Project
BaV4O9 crystallizes in the monoclinic P2/c space group. The structure is three-dimensional. Ba2+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of Ba–O bond distances ranging from 2.75–3.22 Å. There are two inequivalent V4+ sites. In the first V4+ site, V4+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of V–O bond distances ranging from 1.67–2.32 Å. In the second V4+ site, V4+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing VO6 octahedra. The corner-sharing octahedral tilt angles are 61°. There are a spread of V–O bond distances ranging from 1.78–2.05 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded to four V4+ atoms to form a mixture of distorted corner and edge-sharing OV4 trigonal pyramids. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Ba2+ and three V4+ atoms. In the third O2- site, O2- is bonded to four V4+ atoms to form a mixture of distorted corner and edge-sharing OV4 trigonal pyramids. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent Ba2+ and one V4+ atom. In the fifth O2- site, O2- is bonded in a distorted water-like geometry to two equivalent Ba2+ and two V4+ atoms.