Materials Data on TiNb(BiO3)3 by Materials Project
Bi3TiNbO9 crystallizes in the tetragonal I4mm space group. The structure is two-dimensional and consists of two water molecules; two Bi2O3 sheets oriented in the (0, 0, 1) direction; and two TiNbBiO5 sheets oriented in the (0, 0, 1) direction. In each Bi2O3 sheet, there are two inequivalent Bi3+ sites. In the first Bi3+ site, Bi3+ is bonded in a 4-coordinate geometry to four equivalent O2- atoms. All Bi–O bond lengths are 2.14 Å. In the second Bi3+ site, Bi3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are four shorter (2.46 Å) and four longer (2.61 Å) Bi–O bond lengths. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to four Bi3+ atoms to form a mixture of distorted edge and corner-sharing OBi4 tetrahedra. In the second O2- site, O2- is bonded in a distorted square co-planar geometry to four equivalent Bi3+ atoms. In each TiNbBiO5 sheet, Ti4+ is bonded to five O2- atoms to form corner-sharing TiO5 square pyramids. There is four shorter (1.84 Å) and one longer (1.93 Å) Ti–O bond length. Nb5+ is bonded in a 4-coordinate geometry to four equivalent O2- atoms. All Nb–O bond lengths are 2.05 Å. Bi3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are four shorter (2.48 Å) and four longer (2.59 Å) Bi–O bond lengths. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Nb5+ and two equivalent Bi3+ atoms. In the second O2- site, O2- is bonded in a linear geometry to two equivalent Ti4+ atoms. In the third O2- site, O2- is bonded in a distorted single-bond geometry to one Ti4+ and four equivalent Bi3+ atoms.