Materials Data on BaBi2Br2O5 by Materials Project
BaBi2O5Br2 crystallizes in the tetragonal I4mm space group. The structure is two-dimensional and consists of two BaBi2O5Br2 sheets oriented in the (0, 0, 1) direction. Ba2+ is bonded to twelve O2- atoms to form a mixture of face and corner-sharing BaO12 cuboctahedra. There are eight shorter (2.90 Å) and four longer (3.24 Å) Ba–O bond lengths. There are two inequivalent Bi5+ sites. In the first Bi5+ site, Bi5+ is bonded in a 4-coordinate geometry to four equivalent O2- and four equivalent Br1- atoms. All Bi–O bond lengths are 2.34 Å. All Bi–Br bond lengths are 3.32 Å. In the second Bi5+ site, Bi5+ is bonded in a 6-coordinate geometry to five O2- and one Br1- atom. There are four shorter (2.10 Å) and one longer (2.22 Å) Bi–O bond lengths. The Bi–Br bond length is 2.61 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent Ba2+ and two equivalent Bi5+ atoms. In the second O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two equivalent Ba2+ and two equivalent Bi5+ atoms. In the third O2- site, O2- is bonded to four equivalent Ba2+ and one Bi5+ atom to form a mixture of distorted edge and corner-sharing OBa4Bi square pyramids. There are two inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in a single-bond geometry to one Bi5+ atom. In the second Br1- site, Br1- is bonded in a 4-coordinate geometry to four equivalent Bi5+ atoms.